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diff --git a/libtecla-1.4.1/man3/gl_get_line.3 b/libtecla-1.4.1/man3/gl_get_line.3 new file mode 100644 index 0000000..51fc9d8 --- /dev/null +++ b/libtecla-1.4.1/man3/gl_get_line.3 @@ -0,0 +1,2329 @@ +.\" Copyright (C) 2000, 2001 by Martin C. Shepherd +.\" +.\" All rights reserved. +.\" +.\" Permission is hereby granted, free of charge, to any person obtaining a +.\" copy of this software and associated documentation files (the +.\" "Software"), to deal in the Software without restriction, including +.\" without limitation the rights to use, copy, modify, merge, publish, +.\" distribute, and/or sell copies of the Software, and to permit persons +.\" to whom the Software is furnished to do so, provided that the above +.\" copyright notice(s) and this permission notice appear in all copies of +.\" the Software and that both the above copyright notice(s) and this +.\" permission notice appear in supporting documentation. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS +.\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT +.\" OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR +.\" HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL +.\" INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING +.\" FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, +.\" NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION +.\" WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +.\" +.\" Except as contained in this notice, the name of a copyright holder +.\" shall not be used in advertising or otherwise to promote the sale, use +.\" or other dealings in this Software without prior written authorization +.\" of the copyright holder. +.TH gl_get_line 3 +.SH NAME +gl_get_line, new_GetLine, del_GetLine, gl_customize_completion, gl_change_terminal, gl_configure_getline, gl_load_history, gl_save_history, gl_group_history, gl_show_history, gl_watch_fd, gl_terminal_size, gl_resize_history, gl_limit_history, gl_clear_history, gl_toggle_history, gl_lookup_history, gl_state_of_history, gl_range_of_history, gl_size_of_history, gl_echo_mode, gl_replace_prompt, gl_prompt_style, gl_ignore_signal, gl_trap_signal, gl_last_signal \- allow the user to compose an input line +.SH SYNOPSIS +.nf +#include <stdio.h> +#include <libtecla.h> + +GetLine *new_GetLine(size_t linelen, size_t histlen); + +GetLine *del_GetLine(GetLine *gl); + +char *gl_get_line(GetLine *gl, const char *prompt, + const char *start_line, int start_pos); + +int gl_customize_completion(GetLine *gl, void *data, + CplMatchFn *match_fn); + +int gl_change_terminal(GetLine *gl, FILE *input_fp, + FILE *output_fp, const char *term); + +int gl_configure_getline(GetLine *gl, + const char *app_string, + const char *app_file, + const char *user_file); + +int gl_save_history(GetLine *gl, const char *filename, + const char *comment, int max_lines); + +int gl_load_history(GetLine *gl, const char *filename, + const char *comment); + +int gl_watch_fd(GetLine *gl, int fd, GlFdEvent event, + GlFdEventFn *callback, void *data); + +int gl_group_history(GetLine *gl, unsigned stream); + +int gl_show_history(GetLine *gl, FILE *fp, + const char *fmt, int all_groups, + int max_lines); + +int gl_resize_history(GetLine *gl, size_t bufsize); + +void gl_limit_history(GetLine *gl, int max_lines); + +void gl_clear_history(GetLine *gl, int all_groups); + +void gl_toggle_history(GetLine *gl, int enable); + +GlTerminalSize gl_terminal_size(GetLine *gl, + int def_ncolumn, + int def_nline); + +int gl_lookup_history(GetLine *gl, unsigned long id, + GlHistoryLine *hline); + +void gl_state_of_history(GetLine *gl, + GlHistoryState *state); + +void gl_range_of_history(GetLine *gl, + GlHistoryRange *range); + +void gl_size_of_history(GetLine *gl, GlHistorySize *size); + +void gl_echo_mode(GetLine *gl, int enable); + +void gl_replace_prompt(GetLine *gl, const char *prompt); + +void gl_prompt_style(GetLine *gl, GlPromptStyle style); + +int gl_ignore_signal(GetLine *gl, int signo); + +int gl_trap_signal(GetLine *gl, int signo, unsigned flags, + GlAfterSignal after, int errno_value); + +int gl_last_signal(const GetLine *gl); + +.fi + +.SH DESCRIPTION + +The \f3gl_get_line()\f1 function is part of the tecla library (see +the libtecla(3) man page). If the user is typing at a terminal, it +prompts them for an line of input, then provides interactive editing +facilities, similar to those of the unix \f3tcsh\f1 shell. In addition +to simple command-line editing, it supports recall of previously +entered command lines, TAB completion of file names, and in-line +wild-card expansion of filenames. +.sp +.SH AN EXAMPLE + +The following shows a complete example of how to use the +\f3gl_get_line()\f1 function to get input from the user: + +.nf + #include <stdio.h> + #include <locale.h> + #include <libtecla.h> + + int main(int argc, char *argv[]) + { + char *line; /* The line that the user typed */ + GetLine *gl; /* The gl_get_line() resource object */ + + setlocale(LC_CTYPE, ""); /* Adopt the user's choice */ + /* of character set. */ + + gl = new_GetLine(1024, 2048); + if(!gl) + return 1; + + while((line=gl_get_line(gl, "$ ", NULL, -1)) != NULL && + strcmp(line, "exit\\n") != 0) + printf("You typed: %s\\n", line); + + gl = del_GetLine(gl); + return 0; + } +.fi +.sp +In the example, first the resources needed by the \f3gl_get_line()\f1 function +are created by calling \f3new_GetLine()\f1. This allocates the memory used in +subsequent calls to the \f3gl_get_line()\f1 function, including the history +buffer for recording previously entered lines. Then one or more lines are read +from the user, until either an error occurs, or the user types \f3exit\f1. Then +finally the resources that were allocated by \f3new_GetLine()\f1, are returned +to the system by calling \f3del_GetLine()\f1. Note the use of the \f3NULL\f1 +return value of \f3del_GetLine()\f1 to make \f3gl\f1 \f3NULL\f1. This is a +safety precaution. If the program subsequently attempts to pass \f3gl\f1 to +\f3gl_get_line()\f1, said function will complain, and return an error, instead of +attempting to use the deleted resource object. + +.sp +.SH THE FUNCTIONS USED IN THE EXAMPLE +The descriptions of the functions used in the example are as follows: +.sp +.nf + GetLine *new_GetLine(size_t linelen, size_t histlen) +.fi +.sp +This function creates the resources used by the \f3gl_get_line()\f1 +function and returns an opaque pointer to the object that contains +them. The maximum length of an input line is specified via the +\f3linelen\f1 argument, and the number of bytes to allocate for +storing history lines is set by the \f3histlen\f1 argument. History +lines are stored back-to-back in a single buffer of this size. Note +that this means that the number of history lines that can be stored at +any given time, depends on the lengths of the individual lines. If +you want to place an upper limit on the number of lines that can be +stored, see the \f3gl_limit_history()\f1 function described later. If +you don't want history at all, specify \f3histlen\f1 as zero, and no +history buffer will be allocated. +.sp +On error, a message is printed to \f3stderr\f1 and \f3NULL\f1 is returned. +.sp +.nf + GetLine *del_GetLine(GetLine *gl) +.fi +.sp +This function deletes the resources that were returned by a previous +call to \f3new_GetLine()\f1. It always returns \f3NULL\f1 (ie a +deleted object). It does nothing if the \f3gl\f1 argument is +\f3NULL\f1. +.sp +.nf + char *gl_get_line(GetLine *gl, const char *prompt, + const char *start_line, int start_pos); +.fi +.sp +The \f3gl_get_line()\f1 function can be called any number of +times to read input from the user. The \f3gl\f1 argument +must have been previously returned by a call to +\f3new_GetLine()\f1. The \f3prompt\f1 argument should be a +normal \f3NUL\f1 terminated string, specifying the prompt to +present the user with. By default prompts are displayed +literally, but if enabled with the \f3gl_prompt_style()\f1 +function (see later), prompts can contain directives to do +underlining, switch to and from bold fonts, or turn +highlighting on and off. + +If you want to specify the initial contents of the line, for +the user to edit, pass the desired string via the +\f3start_line\f1 argument. You can then specify which +character of this line the cursor is initially positioned +over, using the \f3start_pos\f1 argument. This should be -1 +if you want the cursor to follow the last character of the +start line. If you don't want to preload the line in this +manner, send \f3start_line\f1 as \f3NULL\f1, and set +\f3start_pos\f1 to -1. + +The \f3gl_get_line()\f1 function returns a pointer to the line entered +by the user, or \f3NULL\f1 on error or at the end of the input. The +returned pointer is part of the specified \f3gl\f1 resource object, +and thus should not be free'd by the caller, or assumed to be +unchanging from one call to the next. When reading from a user at a +terminal, there will always be a newline character at the end of the +returned line. When standard input is being taken from a pipe or a +file, there will similarly be a newline unless the input line was too +long to store in the internal buffer. In the latter case you should +call \f3gl_get_line()\f1 again to read the rest of the line. Note that +this behavior makes \f3gl_get_line()\f1 similar to \f3fgets()\f1. In +fact when \f3stdin\f1 isn't connected to a terminal,\f3gl_get_line()\f1 +just calls \f3fgets()\f1. + +.SH OPTIONAL PROMPT FORMATTING + +Whereas by default the prompt string that you specify is +displayed literally, without any special interpretation of +the characters within it, the \f3gl_prompt_style()\f1 +function can be used to enable optional formatting +directives within the prompt. +.sp +.nf + void gl_prompt_style(GetLine *gl, GlPromptStyle style); +.fi +.sp +The \f3style\f1 argument, which specifies the formatting +style, can take any of the following values: +.sp +.nf + GL_FORMAT_PROMPT - In this style, the formatting + directives described below, when + included in prompt strings, are + interpreted as follows: + + %B - Display subsequent + characters with a bold + font. + %b - Stop displaying characters + with the bold font. + %F - Make subsequent characters + flash. + %f - Turn off flashing + characters. + %U - Underline subsequent + characters. + %u - Stop underlining + characters. + %P - Switch to a pale (half + brightness) font. + %p - Stop using the pale font. + %S - Highlight subsequent + characters (also known as + standout mode). + %s - Stop highlighting + characters. + %V - Turn on reverse video. + %v - Turn off reverse video. + %% - Display a single % + character. + + For example, in this mode, a prompt + string like \f3"%UOK%u$ "\f1 would + display the prompt \f3"OK$ "\f1, + but with the \f3OK\f1 part + underlined. + + Note that although a pair of + characters that starts with a % + character, but doesn't match any of + the above directives is displayed + literally, if a new directive is + subsequently introduced which does + match, the displayed prompt will + change, so it is better to always + use %% to display a literal %. + + Also note that not all terminals + support all of these text + attributes, and that some substitute + a different attribute for missing + ones. + + GL_LITERAL_PROMPT - In this style, the prompt string is + printed literally. This is the + default style. +.fi +.sp + +.SH THE AVAILABLE KEY BINDING FUNCTIONS + +The \f3gl_get_line()\f1 function provides a number of functions which +can be bound to key sequences. The names of these functions, and what +they do, are given below. + +.nf + user-interrupt - Send a SIGINT signal to the + parent process. + abort - Send a SIGABRT signal to the + parent process. + suspend - Suspend the parent process. + stop-output - Pause terminal output. + start-output - Resume paused terminal output. + literal-next - Arrange for the next character + to be treated as a normal + character. This allows control + characters to be entered. + cursor-right - Move the cursor one character + right. + cursor-left - Move the cursor one character + left. + insert-mode - Toggle between insert mode and + overwrite mode. + beginning-of-line - Move the cursor to the + beginning of the line. + end-of-line - Move the cursor to the end of + the line. + delete-line - Delete the contents of the + current line. + kill-line - Delete everything that follows + the cursor. + backward-kill-line - Delete all characters between + the cursor and the start of the + line. + forward-word - Move to the end of the word + which follows the cursor. + forward-to-word - Move the cursor to the start of + the word that follows the + cursor. + backward-word - Move to the start of the word + which precedes the cursor. + goto-column - Move the cursor to the + 1-relative column in the line + specified by any preceding + digit-argument sequences (see + ENTERING REPEAT COUNTS below). + find-parenthesis - If the cursor is currently + over a parenthesis character, + move it to the matching + parenthesis character. If not + over a parenthesis character + move right to the next close + parenthesis. + forward-delete-char - Delete the character under the + cursor. + backward-delete-char - Delete the character which + precedes the cursor. + list-or-eof - This is intended for binding + to ^D. When invoked when the + cursor is within the line it + displays all possible + completions then redisplays + the line unchanged. When + invoked on an empty line, it + signals end-of-input (EOF) to + the caller of gl_get_line(). + del-char-or-list-or-eof - This is intended for binding + to ^D. When invoked when the + cursor is within the line it + invokes forward-delete-char. + When invoked at the end of the + line it displays all possible + completions then redisplays + the line unchanged. When + invoked on an empty line, it + signals end-of-input (EOF) to + the caller of gl_get_line(). + forward-delete-word - Delete the word which follows + the cursor. + backward-delete-word - Delete the word which precedes + the cursor. + upcase-word - Convert all of the characters + of the word which follows the + cursor, to upper case. + downcase-word - Convert all of the characters + of the word which follows the + cursor, to lower case. + capitalize-word - Capitalize the word which + follows the cursor. + change-case - If the next character is upper + case, toggle it to lower case + and vice versa. + redisplay - Redisplay the line. + clear-screen - Clear the terminal, then + redisplay the current line. + transpose-chars - Swap the character under the + cursor with the character just + before the cursor. + set-mark - Set a mark at the position of + the cursor. + exchange-point-and-mark - Move the cursor to the last + mark that was set, and move + the mark to where the cursor + used to be. + kill-region - Delete the characters that lie + between the last mark that was + set, and the cursor. + copy-region-as-kill - Copy the text between the mark + and the cursor to the cut + buffer, without deleting the + original text. + yank - Insert the text that was last + deleted, just before the + current position of the cursor. + append-yank - Paste the current contents of + the cut buffer, after the + cursor. + up-history - Recall the next oldest line + that was entered. Note that + in vi mode you are left in + command mode. + down-history - Recall the next most recent + line that was entered. If no + history recall session is + currently active, the next + line from a previous recall + session is recalled. Note that + in vi mode you are left in + command mode. + history-search-backward - Recall the next oldest line + who's prefix matches the string + which currently precedes the + cursor (in vi command-mode the + character under the cursor is + also included in the search + string). Note that in vi mode + you are left in command mode. + history-search-forward - Recall the next newest line + who's prefix matches the string + which currently precedes the + cursor (in vi command-mode the + character under the cursor is + also included in the search + string). Note that in vi mode + you are left in command mode. + history-re-search-backward -Recall the next oldest line + who's prefix matches that + established by the last + invocation of either + history-search-forward or + history-search-backward. + history-re-search-forward - Recall the next newest line + who's prefix matches that + established by the last + invocation of either + history-search-forward or + history-search-backward. + complete-word - Attempt to complete the + incomplete word which + precedes the cursor. Unless + the host program has customized + word completion, filename + completion is attempted. In vi + commmand mode the character + under the cursor is also + included in the word being + completed, and you are left in + vi insert mode. + expand-filename - Within the command line, expand + wild cards, tilde expressions + and dollar expressions in the + filename which immediately + precedes the cursor. In vi + commmand mode the character + under the cursor is also + included in the filename being + expanded, and you are left in + vi insert mode. + list-glob - List any filenames which match + the wild-card, tilde and dollar + expressions in the filename + which immediately precedes the + cursor, then redraw the input + line unchanged. + list-history - Display the contents of the + history list for the current + history group. If a repeat + count of > 1 is specified, + only that many of the most + recent lines are displayed. + See the "ENTERING REPEAT + COUNTS" section. + read-from-file - Temporarily switch to reading + input from the file who's + name precedes the cursor. + read-init-files - Re-read teclarc configuration + files. + beginning-of-history - Move to the oldest line in the + history list. Note that in vi + mode you are left in command + mode. + end-of-history - Move to the newest line in the + history list (ie. the current + line). Note that in vi mode + this leaves you in command + mode. + digit-argument - Enter a repeat count for the + next key-binding function. + For details, see the ENTERING + REPEAT COUNTS section. + newline - Terminate and return the + current contents of the + line, after appending a + newline character. The newline + character is normally '\\n', + but will be the first + character of the key-sequence + that invoked the newline + action, if this happens to be + a printable character. If the + action was invoked by the + '\\n' newline character or the + '\\r' carriage return + character, the line is + appended to the history + buffer. + repeat-history - Return the line that is being + edited, then arrange for the + next most recent entry in the + history buffer to be recalled + when \f3gl_get_line()\f1 is + next called. Repeatedly + invoking this action causes + successive historical input + lines to be re-executed. Note + that this action is equivalent + to the 'Operate' action in + ksh. + ring-bell - Ring the terminal bell, unless + the bell has been silenced via + the \f3nobeep\f1 configuration + option (see the THE TECLA + CONFIGURATION FILE section). + forward-copy-char - Copy the next character into + the cut buffer (NB. use repeat + counts to copy more than one). + backward-copy-char - Copy the previous character + into the cut buffer. + forward-copy-word - Copy the next word into the cut + buffer. + backward-copy-word - Copy the previous word into the + cut buffer. + forward-find-char - Move the cursor to the next + occurrence of the next + character that you type. + backward-find-char - Move the cursor to the last + occurrence of the next + character that you type. + forward-to-char - Move the cursor to the + character just before the next + occurrence of the next + character that the user types. + backward-to-char - Move the cursor to the + character just after the last + occurrence before the cursor + of the next character that the + user types. + repeat-find-char - Repeat the last + backward-find-char, + forward-find-char, + backward-to-char or + forward-to-char. + invert-refind-char - Repeat the last + backward-find-char, + forward-find-char, + backward-to-char, or + forward-to-char in the + opposite direction. + delete-to-column - Delete the characters from the + cursor up to the column that + is specified by the repeat + count. + delete-to-parenthesis - Delete the characters from the + cursor up to and including + the matching parenthesis, or + next close parenthesis. + forward-delete-find - Delete the characters from the + cursor up to and including the + following occurence of the + next character typed. + backward-delete-find - Delete the characters from the + cursor up to and including the + preceding occurence of the + next character typed. + forward-delete-to - Delete the characters from the + cursor up to, but not + including, the following + occurence of the next + character typed. + backward-delete-to - Delete the characters from the + cursor up to, but not + including, the preceding + occurence of the next + character typed. + delete-refind - Repeat the last *-delete-find + or *-delete-to action. + delete-invert-refind - Repeat the last *-delete-find + or *-delete-to action, in the + opposite direction. + copy-to-column - Copy the characters from the + cursor up to the column that + is specified by the repeat + count, into the cut buffer. + copy-to-parenthesis - Copy the characters from the + cursor up to and including + the matching parenthesis, or + next close parenthesis, into + the cut buffer. + forward-copy-find - Copy the characters from the + cursor up to and including the + following occurence of the + next character typed, into the + cut buffer. + backward-copy-find - Copy the characters from the + cursor up to and including the + preceding occurence of the + next character typed, into the + cut buffer. + forward-copy-to - Copy the characters from the + cursor up to, but not + including, the following + occurence of the next + character typed, into the cut + buffer. + backward-copy-to - Copy the characters from the + cursor up to, but not + including, the preceding + occurence of the next + character typed, into the cut + buffer. + copy-refind - Repeat the last *-copy-find + or *-copy-to action. + copy-invert-refind - Repeat the last *-copy-find + or *-copy-to action, in the + opposite direction. + vi-mode - Switch to vi mode from emacs + mode. + emacs-mode - Switch to emacs mode from vi + mode. + vi-insert - From vi command mode, switch to + insert mode. + vi-overwrite - From vi command mode, switch to + overwrite mode. + vi-insert-at-bol - From vi command mode, move the + cursor to the start of the line + and switch to insert mode. + vi-append-at-eol - From vi command mode, move the + cursor to the end of the line + and switch to append mode. + vi-append - From vi command mode, move the + cursor one position right, and + switch to insert mode. + vi-replace-char - From vi command mode, replace + the character under the cursor + with the the next character + entered. + vi-forward-change-char - From vi command mode, delete + the next character then enter + insert mode. + vi-backward-change-char - From vi command mode, delete + the preceding character then + enter insert mode. + vi-forward-change-word - From vi command mode, delete + the next word then enter + insert mode. + vi-backward-change-word - From vi command mode, delete + the preceding word then + enter insert mode. + vi-change-rest-of-line - From vi command mode, delete + from the cursor to the end of + the line, then enter insert + mode. + vi-change-line - From vi command mode, delete + the current line, then enter + insert mode. + vi-change-to-bol - From vi command mode, delete + all characters between the + cursor and the beginning of + the line, then enter insert + mode. + vi-change-to-column - From vi command mode, delete + the characters from the cursor + up to the column that is + specified by the repeat count, + then enter insert mode. + vi-change-to-parenthesis - Delete the characters from the + cursor up to and including + the matching parenthesis, or + next close parenthesis, then + enter vi insert mode. + vi-forward-change-find - From vi command mode, delete + the characters from the + cursor up to and including the + following occurence of the + next character typed, then + enter insert mode. + vi-backward-change-find - From vi command mode, delete + the characters from the + cursor up to and including the + preceding occurence of the + next character typed, then + enter insert mode. + vi-forward-change-to - From vi command mode, delete + the characters from the + cursor up to, but not + including, the following + occurence of the next + character typed, then enter + insert mode. + vi-backward-change-to - From vi command mode, delete + the characters from the + cursor up to, but not + including, the preceding + occurence of the next + character typed, then enter + insert mode. + vi-change-refind - Repeat the last + vi-*-change-find or + vi-*-change-to action. + vi-change-invert-refind - Repeat the last + vi-*-change-find or + vi-*-change-to action, in the + opposite direction. + vi-undo - In vi mode, undo the last + editing operation. + vi-repeat-change - In vi command mode, repeat the + last command that modified the + line. +.fi + +.SH DEFAULT KEY BINDINGS IN EMACS MODE + +The following default key bindings, which can be overriden by +the tecla configuration file, are designed to mimic most of +the bindings of the unix \f3tcsh\f1 shell, when it is in +emacs editing mode. +.sp +This is the default editing mode of the tecla library. +.sp +Note that a key sequence like \f3^A\f1 or \f3C-a\f1 means hold the control-key +down while pressing the letter \f3A\f1, and that where you see \f3\\E\f1 or +\f3M-\f1 in a binding, this represents the escape key or the Meta modifier +key. Also note that to \f3gl_get_line()\f1, pressing the escape key before a +key is equivalent to pressing the meta key at the same time as that key. Thus +the key sequence \f3M-p\f1 can be typed in two ways, by pressing the escape +key, followed by pressing \f3p\f1, or by pressing the Meta key at the same time +as \f3p\f1. +.sp +Under UNIX the terminal driver sets a number of special keys for certain +functions. The tecla library attempts to use the same keybindings to maintain +consistency. The key sequences shown for the following 6 bindings are thus just +examples of what they will probably be set to. If you have used the \f3stty\f1 +command to change these keys, then the default bindings should match. + +.nf + ^C -> user-interrupt + ^\\ -> abort + ^Z -> suspend + ^Q -> start-output + ^S -> stop-output + ^V -> literal-next +.fi + +The cursor keys are refered to by name, as follows. This is necessary +because different types of terminals generate different key sequences +when their cursor keys are pressed. + + right -> cursor-right + left -> cursor-left + up -> up-history + down -> down-history + +The remaining bindings don't depend on the terminal setttings. + +.nf + ^F -> cursor-right + ^B -> cursor-left + M-i -> insert-mode + ^A -> beginning-of-line + ^E -> end-of-line + ^U -> delete-line + ^K -> kill-line + M-f -> forward-word + M-b -> backward-word + ^D -> del-char-or-list-or-eof + ^H -> backward-delete-char + ^? -> backward-delete-char + M-d -> forward-delete-word + M-^H -> backward-delete-word + M-^? -> backward-delete-word + M-u -> upcase-word + M-l -> downcase-word + M-c -> capitalize-word + ^R -> redisplay + ^L -> clear-screen + ^T -> transpose-chars + ^@ -> set-mark + ^X^X -> exchange-point-and-mark + ^W -> kill-region + M-w -> copy-region-as-kill + ^Y -> yank + ^P -> up-history + ^N -> down-history + M-p -> history-search-backward + M-n -> history-search-forward + ^I -> complete-word + ^X* -> expand-filename + ^X^F -> read-from-file + ^X^R -> read-init-files + ^Xg -> list-glob + ^Xh -> list-history + M-< -> beginning-of-history + M-> -> end-of-history + \\n -> newline + \\r -> newline + M-o -> repeat-history + M-^V -> vi-mode + + M-0, M-1, ... M-9 -> digit-argument (see below) +.fi + +Note that ^I is what the TAB key generates, and that ^@ can be +generated not only by pressing the control key and the @ key +simultaneously, but also by pressing the control key and the space bar +at the same time. + +.SH DEFAULT KEY BINDINGS IN VI MODE + +The following default key bindings are designed to mimic the +vi style of editing as closely as possible. This means that +very few editing functions are provided in the initial +character input mode, editing functions instead being +provided by the vi command mode. Vi command mode is entered +whenever the escape character is pressed, or whenever a +key-sequence that starts with a meta character is entered. In +addition to mimicing vi, libtecla provides bindings for tab +completion, wild-card expansion of file names, and historical +line recall. +.sp +To learn how to tell the tecla library to use vi mode instead +of the default emacs editing mode, see the section entitled +THE TECLA CONFIGURATION FILE. +.sp +As already mentioned above in the emacs section, Note that a +key sequence like \f3^A\f1 or \f3C-a\f1 means hold the +control-key down while pressing the letter \f3A\f1, and that +where you see \f3\\E\f1 or \f3M-\f1 in a binding, this +represents the escape key or the Meta modifier key. Also note +that to \f3gl_get_line()\f1, pressing the escape key before a +key is equivalent to pressing the meta key at the same time +as that key. Thus the key sequence \f3M-p\f1 can be typed in +two ways, by pressing the escape key, followed by pressing +\f3p\f1, or by pressing the Meta key at the same time as +\f3p\f1. +.sp +Under UNIX the terminal driver sets a number of special keys +for certain functions. The tecla library attempts to use the +same keybindings to maintain consistency, binding them both +in input mode and in command mode. The key sequences shown +for the following 6 bindings are thus just examples of what +they will probably be set to. If you have used the \f3stty\f1 +command to change these keys, then the default bindings +should match. + +.nf + ^C -> user-interrupt + ^\\ -> abort + ^Z -> suspend + ^Q -> start-output + ^S -> stop-output + ^V -> literal-next + M-^C -> user-interrupt + M-^\\ -> abort + M-^Z -> suspend + M-^Q -> start-output + M-^S -> stop-output +.fi + +Note that above, most of the bindings are defined twice, once +as a raw control code like \f3^C\f1 and then a second time as +a meta character like \f3M-^C\f1. The former is the binding +for vi input mode, whereas the latter is the binding for vi +command mode. Once in command mode all key-sequences that the +user types that they don't explicitly start with an escape or +a meta key, have their first key secretly converted to a meta +character before the key sequence is looked up in the key +binding table. Thus, once in command mode, when you type the +letter \f3i\f1, for example, the tecla library actually looks +up the binding for \f3M-i\f1. + +The cursor keys are refered to by name, as follows. This is necessary +because different types of terminals generate different key sequences +when their cursor keys are pressed. + + right -> cursor-right + left -> cursor-left + up -> up-history + down -> down-history + +The cursor keys normally generate a keysequence that start +with an escape character, so beware that using the arrow keys +will put you into command mode (if you aren't already in +command mode). +.sp +The following are the terminal-independent key bindings for vi input +mode. + +.nf + ^D -> list-or-eof + ^G -> list-glob + ^H -> backward-delete-char + ^I -> complete-word + \\r -> newline + \\n -> newline + ^L -> clear-screen + ^N -> down-history + ^P -> up-history + ^R -> redisplay + ^U -> backward-kill-line + ^W -> backward-delete-word + ^X* -> expand-filename + ^X^F -> read-from-file + ^X^R -> read-init-files + ^? -> backward-delete-char +.fi + +The following are the key bindings that are defined in vi +command mode, this being specified by them all starting with +a meta character. As mentioned above, once in command mode +the initial meta character is optional. For example, you +might enter command mode by typing Esc, and then press h +twice to move the cursor two positions to the left. Both h +characters get quietly converted to M-h before being compared +to the key-binding table, the first one because Escape +followed by a character is always converted to the equivalent +meta character, and the second because command mode was +already active. + +.nf + M-\\ -> cursor-right (Meta-space) + M-$ -> end-of-line + M-* -> expand-filename + M-+ -> down-history + M-- -> up-history + M-< -> beginning-of-history + M-> -> end-of-history + M-^ -> beginning-of-line + M-; -> repeat-find-char + M-, -> invert-refind-char + M-| -> goto-column + M-~ -> change-case + M-. -> vi-repeat-change + M-% -> find-parenthesis + M-a -> vi-append + M-A -> vi-append-at-eol + M-b -> backward-word + M-B -> backward-word + M-C -> vi-change-rest-of-line + M-cb -> vi-backward-change-word + M-cB -> vi-backward-change-word + M-cc -> vi-change-line + M-ce -> vi-forward-change-word + M-cE -> vi-forward-change-word + M-cw -> vi-forward-change-word + M-cW -> vi-forward-change-word + M-cF -> vi-backward-change-find + M-cf -> vi-forward-change-find + M-cT -> vi-backward-change-to + M-ct -> vi-forward-change-to + M-c; -> vi-change-refind + M-c, -> vi-change-invert-refind + M-ch -> vi-backward-change-char + M-c^H -> vi-backward-change-char + M-c^? -> vi-backward-change-char + M-cl -> vi-forward-change-char + M-c\\ -> vi-forward-change-char (Meta-c-space) + M-c^ -> vi-change-to-bol + M-c0 -> vi-change-to-bol + M-c$ -> vi-change-rest-of-line + M-c| -> vi-change-to-column + M-c% -> vi-change-to-parenthesis + M-dh -> backward-delete-char + M-d^H -> backward-delete-char + M-d^? -> backward-delete-char + M-dl -> forward-delete-char + M-d -> forward-delete-char (Meta-d-space) + M-dd -> delete-line + M-db -> backward-delete-word + M-dB -> backward-delete-word + M-de -> forward-delete-word + M-dE -> forward-delete-word + M-dw -> forward-delete-word + M-dW -> forward-delete-word + M-dF -> backward-delete-find + M-df -> forward-delete-find + M-dT -> backward-delete-to + M-dt -> forward-delete-to + M-d; -> delete-refind + M-d, -> delete-invert-refind + M-d^ -> backward-kill-line + M-d0 -> backward-kill-line + M-d$ -> kill-line + M-D -> kill-line + M-d| -> delete-to-column + M-d% -> delete-to-parenthesis + M-e -> forward-word + M-E -> forward-word + M-f -> forward-find-char + M-F -> backward-find-char + M-- -> up-history + M-h -> cursor-left + M-H -> beginning-of-history + M-i -> vi-insert + M-I -> vi-insert-at-bol + M-j -> down-history + M-J -> history-search-forward + M-k -> up-history + M-K -> history-search-backward + M-l -> cursor-right + M-L -> end-of-history + M-n -> history-re-search-forward + M-N -> history-re-search-backward + M-p -> append-yank + M-P -> yank + M-r -> vi-replace-char + M-R -> vi-overwrite + M-s -> vi-forward-change-char + M-S -> vi-change-line + M-t -> forward-to-char + M-T -> backward-to-char + M-u -> vi-undo + M-w -> forward-to-word + M-W -> forward-to-word + M-x -> forward-delete-char + M-X -> backward-delete-char + M-yh -> backward-copy-char + M-y^H -> backward-copy-char + M-y^? -> backward-copy-char + M-yl -> forward-copy-char + M-y\\ -> forward-copy-char (Meta-y-space) + M-ye -> forward-copy-word + M-yE -> forward-copy-word + M-yw -> forward-copy-word + M-yW -> forward-copy-word + M-yb -> backward-copy-word + M-yB -> backward-copy-word + M-yf -> forward-copy-find + M-yF -> backward-copy-find + M-yt -> forward-copy-to + M-yT -> backward-copy-to + M-y; -> copy-refind + M-y, -> copy-invert-refind + M-y^ -> copy-to-bol + M-y0 -> copy-to-bol + M-y$ -> copy-rest-of-line + M-yy -> copy-line + M-Y -> copy-line + M-y| -> copy-to-column + M-y% -> copy-to-parenthesis + M-^E -> emacs-mode + M-^H -> cursor-left + M-^? -> cursor-left + M-^L -> clear-screen + M-^N -> down-history + M-^P -> up-history + M-^R -> redisplay + M-^D -> list-or-eof + M-^I -> complete-word + M-\\r -> newline + M-\\n -> newline + M-^X^R -> read-init-files + M-^Xh -> list-history + + M-0, M-1, ... M-9 -> digit-argument (see below) +.fi + +Note that ^I is what the TAB key generates. + +.SH ENTERING REPEAT COUNTS + +Many of the key binding functions described previously, take +an optional count, typed in before the target +keysequence. This is interpreted as a repeat count by most +bindings. A notable exception is the goto-column binding, +which interprets the count as a column number. +.sp +By default you can specify this count argument by pressing +the meta key while typing in the numeric count. This relies +on the \f3digit-argument\f1 action being bound to Meta-0, +Meta-1 etc. Once any one of these bindings has been +activated, you can optionally take your finger off the meta +key to type in the rest of the number, since every numeric +digit thereafter is treated as part of the number, unless it +is preceded by the \f3literal-next\f1 binding. As soon as a +non-digit, or literal digit key is pressed the repeat count +is terminated and either causes the just typed character to +be added to the line that many times, or causes the next +key-binding function to be given that argument. +.sp +For example, in emacs mode, typing: +.sp +.nf + M-12a +.fi +.sp +causes the letter 'a' to be added to the line 12 times, +whereas +.sp +.nf + M-4M-c +.fi +.sp +Capitalizes the next 4 words. +.sp +In vi command mode the Meta modifier is automatically added +to all characters typed in, so to enter a count in vi +command-mode, just involves typing in the number, just as at +it does in the vi editor itself. So for example, in vi +command mode, typing: +.sp +.nf + 4w2x +.fi +.sp +moves the cursor four words to the right, then deletes two characters. +.sp +You can also bind \f3digit-argument\f1 to other key sequences. If +these end in a numeric digit, that digit gets appended to the current +repeat count. If it doesn't end in a numeric digit, a new repeat count +is started with a value of zero, and can be completed by typing in the +number, after letting go of the key which triggered the digit-argument +action. + +.SH THE TECLA CONFIGURATION FILE + +By default, the first call to \f3gl_get_line()\f1 looks for a file +called \f3\&.teclarc\f1 in your home directory (ie. \f3~/.teclarc\f1). +If it finds this file, it reads it, interpreting each line as defining +a new key binding or an editing configuration option. Since the emacs +keybindings are installed by default, if you want to use the +non-default vi editing mode, the most important item to go in this +file is the following line: + +.nf + edit-mode vi +.fi + +This will re-configure the default bindings for vi-mode. The +complete set of arguments that this command accepts are: +.sp +.nf + vi - Install key-bindings like those of the vi + editor. + emacs - Install key-bindings like those of the emacs + editor. This is the default. + none - Use just the native line editing facilities + provided by the terminal driver. +.fi +.sp +To prevent the terminal bell from being rung, such as when +an unrecognized control-sequence is typed, place the +following line in the configuration file: + +.nf + nobeep +.fi + +An example of a key binding line in the configuration file is +the following. + +.nf + bind M-[2~ insert-mode +.fi + +On many keyboards, the above key sequence is generated when one +presses the \f3insert\f1 key, so with this keybinding, one can toggle +between the emacs-mode insert and overwrite modes by hitting one +key. One could also do it by typing out the above sequence of +characters one by one. As explained above, the \f3M-\f1 part of this +sequence can be typed either by pressing the escape key before the +following key, or by pressing the Meta key at the same time as the +following key. Thus if you had set the above key binding, and the +insert key on your keyboard didn't generate the above key sequence, +you could still type it in either of the following 2 ways. + +.nf + 1. Hit the escape key momentarily, then press '[', then '2', then + finally '~'. + + 2. Press the meta key at the same time as pressing the '[' key, + then press '2', then '~'. +.fi + +If you set a keybinding for a key-sequence that is already bound to a function, +the new binding overrides the old one. If in the new binding you omit the name +of the new function to bind to the key-sequence, the original binding becomes +undefined. +.sp +Starting with versions of libtecla later than 1.3.3 it is now possible +to bind keysequences that begin with a printable character. Previously +key-sequences were required to start with a control or meta character. +.sp +Note that the special keywords "up", "down", "left" and "right" refer +to the arrow keys, and are thus not treated as keysequences. So, for +example, to rebind the up and down arrow keys to use the history +search mechanism instead of the simple history recall method, you +could place the following in your configuration file: + +.nf + bind up history-search-backwards + bind down history-search-backwards +.fi +.sp +To unbind an existing binding, you can do this with the bind command +by omitting to name any action to rebind the key sequence to. For +example, by not specifying an action function, the following command +unbinds the default beginning-of-line action from the ^A key sequence: + +.nf + bind ^A +.fi + +.SH ALTERNATE CONFIGURATION SOURCES + +As mentioned above, by default users have the option of configuring +the behavior of \f3gl_get_line()\f1 via a configuration file called +\f3\&.teclarc\f1 in their home directories. The fact that all +applications share this same configuration file is both an advantage +and a disadvantage. In most cases it is an advantage, since it +encourages uniformity, and frees the user from having to configure +each application separately. In some applications, however, this +single means of configuration is a problem. This is particularly true +of embedded software, where there's no filesystem to read a +configuration file from, and also in applications where a radically +different choice of keybindings is needed to emulate a legacy keyboard +interface. To cater for such cases, the following function allows the +application to control where configuration information is read from. + +.sp +.nf + int gl_configure_getline(GetLine *gl, + const char *app_string, + const char *app_file, + const char *user_file); +.fi +.sp + +It allows the configuration commands that would normally be read from +a user's \f3~/.teclarc\f1 file, to be read from any or none of, a +string, an application specific configuration file, and/or a +user-specific configuration file. If this function is called before +the first call to \f3gl_get_line()\f1, the default behavior of +reading \f3~/.teclarc\f1 on the first call to \f3gl_get_line()\f1 is +disabled, so all configuration must be achieved using the +configuration sources specified with this function. + +If \f3app_string != NULL\f1, then it is interpreted as a string +containing one or more configuration commands, separated from each +other in the string by embedded newline characters. If \f3app_file != +NULL\f1 then it is interpreted as the full pathname of an +application-specific configuration file. If \f3user_file != NULL\f1 +then it is interpreted as the full pathname of a user-specific +configuration file, such as \f3~/.teclarc\f1. For example, in the +following call, + + gl_configure_getline(gl, "edit-mode vi \\n nobeep", + "/usr/share/myapp/teclarc", + "~/.teclarc"); + +the \f3app_string\f1 argument causes the calling application to start +in vi edit-mode, instead of the default emacs mode, and turns off the +use of the terminal bell by the library. It then attempts to read +system-wide configuration commands from an optional file called +\f3/usr/share/myapp/teclarc\f1, then finally reads user-specific +configuration commands from an optional \f3\&.teclarc\f1 file in the +user's home directory. Note that the arguments are listed in ascending +order of priority, with the contents of \f3app_string\f1 being +potentially overriden by commands in \f3app_file\f1, and commands in +\f3app_file\f1 potentially being overriden by commands in +\f3user_file\f1. +.sp +You can call this function as many times as needed, the results being +cumulative, but note that copies of any filenames specified via the +\f3app_file\f1 and \f3user_file\f1 arguments are recorded internally +for subsequent use by the \f3read-init-files\f1 key-binding function, +so if you plan to call this function multiple times, be sure that the +last call specifies the filenames that you want re-read when the user +requests that the configuration files be re-read. + +.SH FILENAME AND TILDE COMPLETION + +With the default key bindings, pressing the TAB key (aka. ^I) results +in \f3gl_get_line()\f1 attempting to complete the incomplete filename +that precedes the cursor. \f3gl_get_line()\f1 searches backwards from +the cursor, looking for the start of the filename, stopping when it +hits either a space or the start of the line. If more than one file +has the specified prefix, \f3gl_get_line()\f1 completes the filename +up to the point at which the ambiguous matches start to differ, then +lists the possible matches. +.sp +In addition to literally written filenames, \f3gl_get_line()\f1 can +complete files that start with \f3~/\f1 and \f3~user/\f1 expressions +and that contain \f3$envvar\f1 expressions. In particular, if you hit +TAB within an incomplete \f3~user\f1, expression, \f3gl_get_line()\f1 +will attempt to complete the username, listing any ambiguous matches. +.sp +The completion binding is implemented using the +\f3cpl_word_completions()\f1 function, which is also available +separately to users of this library. See the +\f3cpl_word_completions(3)\f1 man page for more details. + +.SH CUSTOMIZED WORD COMPLETION + +If in your application, you would like to have TAB completion complete +other things in addition to or instead of filenames, you can arrange +this by registering an alternate completion callback function, via a +call to the \f3gl_customize_completion()\f1 function. +.sp +.nf + int gl_customize_completion(GetLine *gl, void *data, + CplMatchFn *match_fn); +.fi +.sp +The \f3data\f1 argument provides a way for your application to pass +arbitrary, application-specific information to the callback +function. This is passed to the callback every time that it is +called. It might for example, point to the symbol table from which +possible completions are to be sought. The \f3match_fn\f1 argument +specifies the callback function to be called. The \f3CplMatchFn\f1 +function type is defined in \f3libtecla.h\f1, as is a +\f3CPL_MATCH_FN()\f1 macro that you can use to declare and prototype +callback functions. The declaration and responsibilities of callback +functions are described in depth in the \f1cpl_complete_word(3)\f1 man +page. +.sp +In brief, the callback function is responsible for looking backwards +in the input line, back from the point at which the user pressed TAB, +to find the start of the word being completed. It then must lookup +possible completions of this word, and record them one by one in the +\f3WordCompletion\f1 object that is passed to it as an argument, by +calling the \f3cpl_add_completion()\f1 function. If the callback +function wishes to provide filename completion in addition to its own +specific completions, it has the option of itself calling the builtin +file-name completion callback. This also, is documented in the +\f3cpl_complete_word(3)\f1 man page. +.sp +Note that if you would like \f3gl_get_line()\f1 to return the current +input line when a successful completion is been made, you can arrange +this when you call \f3cpl_add_completion()\f1, by making the last +character of the continuation suffix a newline character. If you do +this, the input line will be updated to display the completion, +together with any contiuation suffix up to the newline character, then +\f3gl_get_line()\f1 will return this input line. + +.SH FILENAME EXPANSION + +With the default key bindings, pressing \f3^X*\f1 causes +\f3gl_get_line()\f1 to expand the filename that precedes the cursor, +replacing \f3~/\f1 and \f3~user/\f1 expressions with the corresponding +home directories, and replacing \f3$envvar\f1 expressions with the +value of the specified environment variable, then if there are any +wildcards, replacing the so far expanded filename with a +space-separated list of the files which match the wild cards. +.sp +The expansion binding is implemented using the \f3ef_expand_file()\f1 function. +See the \f3ef_expand_file(3)\f1 man page for more details. + +.SH RECALLING PREVIOUSLY TYPED LINES + +Every time that a new line is entered by the user, it is appended to a +list of historical input lines maintained within the GetLine resource +object. You can traverse up and down this list using the up and down +arrow keys. Alternatively, you can do the same with the \f3^P\f1, and +\f3^N\f1 keys, and in vi command mode you can alternatively use the k +and j characters. Thus pressing up-arrow once, replaces the current +input line with the previously entered line. Pressing up-arrow again, +replaces this with the line that was entered before it, etc.. Having +gone back one or more lines into the history list, one can return to +newer lines by pressing down-arrow one or more times. If you do this +sufficient times, you will return to the original line that you were +entering when you first hit up-arrow. +.sp +Note that in vi mode, all of the history recall functions switch the +library into command mode. +.sp +In emacs mode the \f3M-p\f1 and \f3M-n\f1 keys work just like the +\f3^P\f1 and \f3^N\f1 keys, except that they skip all but those +historical lines which share the prefix that precedes the cursor. In +vi command mode the upper case \f3K\f1 and \f3J\f1 characters do the +same thing, except that the string that they search for includes the +character under the cursor as well as what precedes it. +.sp +Thus for example, suppose that you were in emacs mode, and you had +just entered the following list of commands in the order shown: + +.nf + ls ~/tecla/ + cd ~/tecla + ls -l getline.c + emacs ~/tecla/getline.c +.fi + +If you next typed: + +.nf + ls +.fi + +and then hit \f3M-p\f1, then rather than returning the previously +typed emacs line, which doesn't start with "ls", \f3gl_get_line()\f1 +would recall the "ls -l getline.c" line. Pressing \f3M-p\f1 again +would recall the "ls ~/tecla/" line. + +.SH HISTORY FILES + +To save the contents of the history buffer before quitting your +application, and subsequently restore them when you next start the +application, the following functions are provided. + +.sp +.nf + int gl_save_history(GetLine *gl, const char *filename, + const char *comment, int max_lines); + int gl_load_history(GetLine *gl, const char *filename, + const char *comment); +.fi +.sp + +The \f3filename\f1 argument specifies the name to give the history +file when saving, or the name of an existing history file, when +loading. This may contain home-directory and environment variable +expressions, such as "~/.myapp_history" or "$HOME/.myapp_history". +.sp +Along with each history line, extra information about it, such as when +it was entered by the user, and what its nesting level is, is recorded +as a comment preceding the line in the history file. Writing this as a +comment allows the history file to double as a command file, just in +case you wish to replay a whole session using it. Since comment +prefixes differ in different languages, the \f3comment\f1 argument is +provided for specifying the comment prefix. For example, if your +application were a unix shell, such as the bourne shell, you would +specify "#" here. Whatever you choose for the comment character, you +must specify the same prefix to \f3gl_load_history()\f1 that you used +when you called \f3gl_save_history()\f1 to write the history file. +.sp +The \f3max_lines\f1 must be either -1 to specify that all lines in the +history list be saved, or a positive number specifying a ceiling on +how many of the most recent lines should be saved. +.sp +Both fuctions return non-zero on error, after writing an error message +to stderr. Note that \f3gl_load_history()\f1 does not consider the +non-existence of a file to be an error. + +.SH MULTIPLE HISTORY LISTS + +If your application uses a single \f3GetLine\f1 object for entering +many different types of input lines, you may wish \f3gl_get_line()\f1 +to distinguish the different types of lines in the history list, and +only recall lines that match the current type of line. To support this +requirement, \f3gl_get_line()\f1 marks lines being recorded in the +history list with an integer identifier chosen by the application. +Initially this identifier is set to \f10\f3 by \f3new_GetLine()\f1, +but it can be changed subsequently by calling +\f3gl_group_history()\f1. + +.sp +.nf + int gl_group_history(GetLine *gl, unsigned id); +.fi +.sp + +The integer identifier \f3id\f1 can be any number chosen by the +application, but note that \f3gl_save_history()\f1 and +\f3gl_load_history()\f1 preserve the association between identifiers +and historical input lines between program invokations, so you should +choose fixed identifiers for the different types of input line used by +your application. +.sp +Whenever \f3gl_get_line()\f1 appends a new input line to the history +list, the current history identifier is recorded with it, and when it +is asked to recall a historical input line, it only recalls lines that +are marked with the current identifier. + +.SH DISPLAYING HISTORY + +The history list can be displayed by calling \f3gl_show_history()\f1. + +.sp +.nf + int gl_show_history(GetLine *gl, FILE *fp, + const char *fmt, + int all_groups, + int max_lines); +.fi +.sp + +This displays the current contents of the history list to the stdio +output stream \f3fp\f1. If the \f3max_lines\f1 argument is greater +than or equal to zero, then no more than this number of the most +recent lines will be displayed. If the \f3all_groups\f1 argument is +non-zero, lines from all history groups are displayed. Otherwise just +those of the currently selected history group are displayed. The +format string argument, \f3fmt\f1, determines how the line is +displayed. This can contain arbitrary characters which are written +verbatim, interleaved with any of the following format directives: + +.nf + %D - The date on which the line was originally + entered, formatted like 2001-11-20. + %T - The time of day when the line was entered, + formatted like 23:59:59. + %N - The sequential entry number of the line in + the history buffer. + %G - The number of the history group which the + line belongs to. + %% - A literal % character. + %H - The history line itself. +.fi + +Thus a format string like \f3"%D %T %H\n"\f1 would output something like: + +.nf + 2001-11-20 10:23:34 Hello world +.fi + +Note the inclusion of an explicit newline character in the format +string. + +.SH LOOKING UP HISTORY + +The \f3gl_lookup_history()\f1 function allows the calling application +to look up lines in the history list. + +.sp +.nf + typedef struct { + const char *line; /* The requested historical */ + /* line. */ + unsigned group; /* The history group to which */ + /* the line belongs. */ + time_t timestamp; /* The date and time at which */ + /* the line was originally */ + /* entered. */ + } GlHistoryLine; + + int gl_lookup_history(GetLine *gl, unsigned long id, + GlHistoryLine *hline); +.fi +.sp + +The \f3id\f1 argument indicates which line to look up, where the first +line that was entered in the history list after \f3new_GetLine()\f1 +was called, is denoted by 0, and subsequently entered lines are +denoted with successively higher numbers. Note that the range of lines +currently preserved in the history list can be queried by calling the +\f3gl_range_of_history()\f1 function, described later. If the +requested line is in the history list, the details of the line are +recorded in the variable pointed to by the \f3hline\f1 argument, and +\f31\f1 is returned. Otherwise \f30\f1 is returned, and the variable +pointed to by \f3hline\f1 is left unchanged. +.sp +Beware that the string returned in \f3hline->line\f1 is part of the +history buffer, so it must not be modified by the caller, and will be +recycled on the next call to any function that takes \f3gl\f1 as its +argument. Therefore you should make a private copy of this string if +you need to keep it around. + +.SH MISCELLANEOUS HISTORY CONFIGURATION + +If you wish to change the size of the history buffer that was +originally specified in the call to \f3new_GetLine()\f1, you can do so +with the \f3gl_resize_history()\f1 function. + +.sp +.nf + int gl_resize_history(GetLine *gl, size_t histlen); +.fi +.sp + +The \f3histlen\f1 argument specifies the new size in bytes, and if you +specify this as 0, the buffer will be deleted. +.sp +As mentioned in the discussion of \f3new_GetLine()\f1, the number of +lines that can be stored in the history buffer, depends on the lengths +of the individual lines. For example, a 1000 byte buffer could equally +store 10 lines of average length 100 bytes, or 2 lines of average +length 50 bytes. Although the buffer is never expanded when new lines +are added, a list of pointers into the buffer does get expanded when +needed to accomodate the number of lines currently stored in the +buffer. To place an upper limit on the number of lines in the buffer, +and thus a ceiling on the amount of memory used in this list, you can +call the \f3gl_limit_history()\f1 function. + +.sp +.nf + void gl_limit_history(GetLine *gl, int max_lines); +.fi +.sp + +The \f3max_lines\f1 should either be a positive number \f3>= 0\f1, +specifying an upper limit on the number of lines in the buffer, or be +\f3-1\f1 to cancel any previously specified limit. When a limit is in +effect, only the \f3max_lines\f1 most recently appended lines are kept +in the buffer. Older lines are discarded. +.sp +To discard lines from the history buffer, use the +\f3gl_clear_history()\f1 function. +.sp +.nf + void gl_clear_history(GetLine *gl, int all_groups); +.fi +.sp +The \f3all_groups\f1 argument tells the function whether to delete +just the lines associated with the current history group (see +\f3gl_group_history()\f1), or all historical lines in the buffer. +.sp +The \f3gl_toggle_history()\f1 function allows you to toggle history on +and off without losing the current contents of the history list. + +.sp +.nf + void gl_toggle_history(GetLine *gl, int enable); +.fi +.sp + +Setting the \f3enable\f1 argument to 0 turns off the history +mechanism, and setting it to 1 turns it back on. When history is +turned off, no new lines will be added to the history list, and +history lookup key-bindings will act as though there is nothing in the +history buffer. + +.SH QUERYING HISTORY INFORMATION + +The configured state of the history list can be queried with the +\f3gl_history_state()\f1 function. + +.sp +.nf + typedef struct { + int enabled; /* True if history is enabled */ + unsigned group; /* The current history group */ + int max_lines; /* The current upper limit on the */ + /* number of lines in the history */ + /* list, or -1 if unlimited. */ + } GlHistoryState; + + void gl_state_of_history(GetLine *gl, + GlHistoryState *state); +.fi +.sp +On return, the status information is recorded in the variable pointed +to by the \f3state\f1 argument. +.sp +The \f3gl_range_of_history()\f1 function returns the number and +range of lines in the history list. + +.sp +.nf +typedef struct { + unsigned long oldest; /* The sequential entry number */ + /* of the oldest line in the */ + /* history list. */ + unsigned long newest; /* The sequential entry number */ + /* of the newest line in the */ + /* history list. */ + int nlines; /* The number of lines in the */ + /* history list. */ +} GlHistoryRange; + +void gl_range_of_history(GetLine *gl, GlHistoryRange *range); +.fi +.sp +The return values are recorded in the variable pointed to by the +\f3range\f1 argument. If the \f3nlines\f1 member of this structure is +greater than zero, then the \f3oldest\f1 and \f3newest\f1 members +report the range of lines in the list, and \f3newest=oldest+nlines-1\f1. +Otherwise they are both zero. +.sp +The \f3gl_size_of_history()\f1 function returns the total size of the +history buffer and the amount of the buffer that is currently +occupied. +.sp +.nf + typedef struct { + size_t size; /* The size of the history buffer */ + /* (bytes). */ + size_t used; /* The number of bytes of the */ + /* history buffer that are */ + /* currently occupied. */ + } GlHistorySize; + + void gl_size_of_history(GetLine *gl, GlHistorySize *size); +.fi +.sp +On return, the size information is recorded in the variable pointed to +by the \f3size\f1 argument. + +.SH CHANGING TERMINALS + +The \f3new_GetLine()\f1 constructor function assumes that input is to +be read from \f3stdin\f1, and output written to \f3stdout\f1. The +following function allows you to switch to different input and output +streams. +.sp +.nf + int gl_change_terminal(GetLine *gl, FILE *input_fp, + FILE *output_fp, const char *term); +.fi +.sp +The \f3gl\f1 argument is the object that was returned by +\f3new_GetLine()\f1. The \f3input_fp\f1 argument specifies the stream +to read from, and \f3output_fp\f1 specifies the stream to be written +to. Only if both of these refer to a terminal, will interactive +terminal input be enabled. Otherwise \f3gl_get_line()\f1 will simply +call \f3fgets()\f1 to read command input. If both streams refer to a +terminal, then they must refer to the same terminal, and the type of +this terminal must be specified via the \f3term\f1 argument. The value +of the \f3term\f1 argument is looked up in the terminal information +database (terminfo or termcap), in order to determine which special +control sequences are needed to control various aspects of the +terminal. \f3new_GetLine()\f1 for example, passes the return value of +\f3getenv("TERM")\f1 in this argument. Note that if one or both of +\f3input_fp\f1 and \f3output_fp\f1 don't refer to a terminal, then it +is legal to pass \f3NULL\f1 instead of a terminal type. +.sp +Note that if you want to pass file descriptors to +\f3gl_change_terminal()\f1, you can do this by creating stdio stream +wrappers using the POSIX \f3fdopen()\f1 function. + +.SH EXTERNAL EVENT HANDLING + +While \f3gl_get_line()\f1 is waiting for keyboard input from the user, +you can ask it to also watch for activity on arbitrary file +descriptors, such as network sockets, pipes etc, and have it call +functions of your choosing when activity is seen. This works on any +system that has the \f3select()\f1 system call, which is most, if not +all flavors of unix. Registering a file descriptor to be watched by +\f3gl_get_line()\f1 involves calling the \f3gl_watch_fd()\f1 function. + +.sp +.nf + int gl_watch_fd(GetLine *gl, int fd, GlFdEvent event, + GlFdEventFn *callback, void *data); +.fi +.sp + +If this returns non-zero, then it means that either your arguments are +invalid, or that this facility isn't supported on the host system. +.sp +The \f3fd\f1 argument is the file descriptor to be watched. The +\f3event\f1 argument specifies what type of activity is of interest, +chosen from the following enumerated values: + +.sp +.nf + GLFD_READ - Watch for the arrival of data to be read. + GLFD_WRITE - Watch for the ability to write to the file + descriptor without blocking. + GLFD_URGENT - Watch for the arrival of urgent + out-of-band data on the file descriptor. +.fi +.sp + +The \f3callback\f1 argument is the function to call when the selected +activity is seen. It should be defined with the following macro, which +is defined in libtecla.h. + +.sp +.nf + #define GL_FD_EVENT_FN(fn) GlFdStatus (fn)(GetLine *gl, \\ + void *data, int fd, \\ + GlFdEvent event) +.fi +.sp +The \f3data\f1 argument of the \f3gl_watch_fd()\f1 function is passed +to the callback function for its own use, and can point to anything +you like, including \f3NULL\f1. The file descriptor and the event +argument are also passed to the callback function, and this +potentially allows the same callback function to be registered to more +than one type of event and/or more than one file descriptor. The +return value of the callback function should be one of the following +values. + +.sp +.nf + GLFD_ABORT - Tell gl_get_line() to abort with an + error (errno won't be set, so set it + appropriately yourself if you need it). + GLFD_REFRESH - Redraw the input line then continue + waiting for input. Return this if + your callback wrote to the terminal. + GLFD_CONTINUE - Continue to wait for input, without + redrawing the line. +.fi +.sp +Note that before calling the callback, \f3gl_get_line()\f1 blocks most +signals, and leaves its own signal handlers installed, so if you need +to catch a particular signal you will need to both temporarily install +your own signal handler, and unblock the signal. Be sure to re-block +the signal (if it was originally blocked) and reinstate the original +signal handler, if any, before returning. +.sp +Your callback shouldn't try to read from the terminal, which is left +in raw mode as far as input is concerned. You can however write to the +terminal as usual, since features like conversion of newline to +carriage-return/linefeed are re-enabled while the callback is +running. If your callback function does write to the terminal, be sure +to output a newline first, and when your callback returns, tell +\f3gl_get_line()\f1 that the input line needs to be redrawn, by +returning the \f3GLFD_REFRESH\f1 status code. +.sp +To remove a callback function that you previously registered for a +given file descriptor and event, simply call \f3gl_watch_fd()\f1 with +the same file descriptor and \f3event\f1 arguments, but with a +\f3callback\f1 argument of \f30\f1. The \f3data\f1 argument is ignored +in this case. + +.SH SIGNAL HANDLING DEFAULTS + +By default, the \f3gl_get_line()\f1 function intercepts a +number of signals. This is particularly important for +signals which would by default terminate the process, since +the terminal needs to be restored to a usable state before +this happens. In this section, the signals that are trapped +by default, and how gl_get_line() responds to them, is +described. Changing these defaults is the topic of the +following section. +.sp +When the following subset of signals are caught, \f3gl_get_line()\f1 +first restores the terminal settings and signal handling to how they +were before \f3gl_get_line()\f1 was called, resends the signal, to +allow the calling application's signal handlers to handle it, then if +the process still exists, \f3gl_get_line()\f1 returns \f3NULL\f1 and +sets \f3errno\f1 as specified below. + +.sp +.nf + SIGINT - This signal is generated both by the keyboard + interrupt key (usually ^C), and the keyboard + break key. + + errno=EINTR + + SIGHUP - This signal is generated when the controlling + terminal exits. + + errno=ENOTTY + + SIGPIPE - This signal is generated when a program attempts + to write to a pipe who's remote end isn't being + read by any process. This can happen for example + if you have called \f3gl_change_terminal()\f1 to + redirect output to a pipe hidden under a pseudo + terminal. + + errno=EPIPE + + SIGQUIT - This signal is generated by the keyboard quit + key (usually ^\\). + + errno=EINTR + + SIGABRT - This signal is generated by the standard C, + abort() function. By default it both + terminates the process and generates a core + dump. + + errno=EINTR + + SIGTERM - This is the default signal that the UN*X + kill command sends to processes. + + errno=EINTR +.fi +.sp +Note that in the case of all of the above signals, POSIX mandates that +by default the process is terminated, with the addition of a core dump +in the case of the \f3SIGQUIT\f1 signal. In other words, if the +calling application doesn't override the default handler by supplying +its own signal handler, receipt of the corresponding signal will +terminate the application before \f3gl_get_line()\f1 returns. +.sp +If gl_get_line() aborts with errno set to EINTR, you can find out what +signal caused it to abort, by calling the following function. +.sp +.nf + int gl_last_signal(const GetLine *gl); +.fi +.sp +This returns the numeric code (eg. \f3SIGINT\f1) of the last signal +that was received during the most recent call to \f3gl_get_line()\f1, +or \f3-1\f1 if no signals were received. +.sp +On systems that support it, when a SIGWINCH (window change) signal is +received, \f3gl_get_line()\f1 queries the terminal to find out its new +size, redraws the current input line to accomodate the new size, then +returns to waiting for keyboard input from the user. Unlike other +signals, this signal isn't resent to the application. +.sp +Finally, the following signals cause \f3gl_get_line()\f1 to first +restore the terminal and signal environment to that which prevailed +before \f3gl_get_line()\f1 was called, then resend the signal to the +application. If the process still exists after the signal has been +delivered, then \f3gl_get_line()\f1 then re-establishes its own signal +handlers, switches the terminal back to raw mode, redisplays the input +line, and goes back to awaiting terminal input from the user. +.sp +.nf + SIGCONT - This signal is generated when a suspended + process is resumed. + + SIGPWR - This signal is generated when a power failure + occurs (presumably when the system is on a + UPS). + + SIGALRM - This signal is generated when a timer + expires. + + SIGUSR1 - An application specific signal. + + SIGUSR2 - Another application specific signal. + + SIGVTALRM - This signal is generated when a virtual + timer expires (see man setitimer(2)). + + SIGXCPU - This signal is generated when a process + exceeds its soft CPU time limit. + + SIGTSTP - This signal is generated by the terminal + suspend key, which is usually ^Z, or the + delayed terminal suspend key, which is + usually ^Y. + + SIGTTIN - This signal is generated if the program + attempts to read from the terminal while the + program is running in the background. + + SIGTTOU - This signal is generated if the program + attempts to write to the terminal while the + program is running in the background. +.fi +.sp + +Obviously not all of the above signals are supported on all systems, +so code to support them is conditionally compiled into the tecla +library. +.sp +Note that if \f3SIGKILL\f1, which by definition can't be caught, or +any of the hardware generated exception signals, such as +\f3SIGSEGV\f1, \f3SIGBUS\f1 and \f3SIGFPE\f1, are received and +unhandled while \f3gl_get_line()\f1 has the terminal in raw mode, the +program will be terminated without the terminal having been restored +to a usable state. In practice, job-control shells usually reset the +terminal settings when a process relinquishes the controlling +terminal, so this is only a problem with older shells. + +.SH CUSTOMIZED SIGNAL HANDLING + +The previous section listed the signals that +\f3gl_get_line()\f1 traps by default, and described how it +responds to them. This section describes how to both add and +remove signals from the list of trapped signals, and how to +specify how \f3gl_get_line()\f1 should respond to a given +signal. +.sp +If you don't need \f3gl_get_line()\f1 to do anything in +response to a signal that it normally traps, you can tell to +\f3gl_get_line()\f1 to ignore that signal by calling +\f3gl_ignore_signal()\f1. +.sp +.nf + int gl_ignore_signal(GetLine *gl, int signo); +.fi +.sp +The \f3signo\f1 argument is the number of the signal +(eg. \f3SIGINT\f1) that you want to have ignored. If the +specified signal isn't currently one of those being trapped, +this function does nothing. +.sp +The \f3gl_trap_signal()\f1 function allows you to either add +a new signal to the list that \f3gl_get_line()\f1 traps, or +modify how it responds to a signal that it already traps. +.sp +.nf + int gl_trap_signal(GetLine *gl, int signo, unsigned flags, + GlAfterSignal after, int errno_value); +.fi +.sp +The \f3signo\f1 argument is the number of the signal that +you wish to have trapped. The \f3flags\f1 argument is a set +of flags which determine the environment in which the +application's signal handler is invoked, the \f3after\f1 +argument tells \f3gl_get_line()\f1 what to do after the +application's signal handler returns, and \f3errno_value\f1 +tells \f3gl_get_line()\f1 what to set \f3errno\f1 to if told +to abort. +.sp +The \f3flags\f1 argument is a bitwise OR of zero or more of +the following enumerators: +.sp +.nf + GLS_RESTORE_SIG - Restore the caller's signal + environment while handling the + signal. + + GLS_RESTORE_TTY - Restore the caller's terminal settings + while handling the signal. + + GLS_RESTORE_LINE - Move the cursor to the start of the + line following the input line before + invoking the application's signal + handler. + + GLS_REDRAW_LINE - Redraw the input line when the + application's signal handler returns. + + GLS_UNBLOCK_SIG - Normally, if the calling program has + a signal blocked (man sigprocmask), + gl_get_line() does not trap that + signal. This flag tells gl_get_line() + to trap the signal and unblock it for + the duration of the call to + gl_get_line(). + + GLS_DONT_FORWARD - If this flag is included, the signal + will not be forwarded to the signal + handler of the calling program. +.fi +.sp +Two commonly useful flag combinations are also enumerated as +follows: +.sp +.nf + GLS_RESTORE_ENV = GLS_RESTORE_SIG | GLS_RESTORE_TTY | + GLS_REDRAW_LINE + + GLS_SUSPEND_INPUT = GLS_RESTORE_ENV | GLS_RESTORE_LINE +.fi +.sp + +If your signal handler, or the default system signal +handler for this signal, if you haven't overriden it, never +either writes to the terminal, nor suspends or terminates +the calling program, then you can safely set the \f3flags\f1 +argument to \f30\f1. +.sp +If your signal handler always writes to the terminal, reads +from it, or suspends or terminates the program, you should +specify the \f3flags\f1 argument as \f3GL_SUSPEND_INPUT\f1, +so that: +.sp +.nf +1. The cursor doesn't get left in the middle of the input + line. +2. So that the user can type in input and have it echoed. +3. So that you don't need to end each output line with + \f3\\r\\n\f1, instead of just \f3\\n\f1. +.fi +.sp +The \f3GL_RESTORE_ENV\f1 combination is the same as +\f3GL_SUSPEND_INPUT\f1, except that it doesn't move the +cursor, and if your signal handler doesn't read or write +anything to the terminal, the user won't see any visible +indication that a signal was caught. This can be useful if +you have a signal handler that only occasionally writes to +the terminal, where using \f3GL_SUSPEND_LINE\f1 would cause +the input line to be unnecessarily duplicated when nothing +had been written to the terminal. Such a signal handler, +when it does write to the terminal, should be sure to start +a new line at the start of its first write, by writing a +'\\n' character, and should be sure to leave the cursor on a +new line before returning. If the signal arrives while the +user is entering a line that only occupies a signal terminal +line, or if the cursor is on the last terminal line of a +longer input line, this will have the same effect as +\f3GL_SUSPEND_INPUT\f1. Otherwise it will start writing on a +line that already contains part of the displayed input line. +This doesn't do any harm, but it looks a bit ugly, which is +why the \f3GL_SUSPEND_INPUT\f1 combination is better if you +know that you are always going to be writting to the +terminal. +.sp +The \f3after\f1 argument, which determines what +\f3gl_get_line()\f1 does after the application's signal +handler returns (if it returns), can take any one of the +following values: +.sp +.nf + GLS_RETURN - Return the completed input line, just as + though the user had pressed the return + key. + + GLS_ABORT - Cause gl_get_line() to return \f3NULL\f1. + + GLS_CONTINUE - Resume command line editing. +.fi +.sp +The \f3errno_value\f1 argument is intended to be combined +with the \f3GLS_ABORT\f1 option, telling \f3gl_get_line()\f1 +what to set the standard \f3errno\f1 variable to before +returning \f3NULL\f1 to the calling program. It can also, +however, be used with the \f3GL_RETURN\f1 option, in case +you wish to have a way to distinguish between an input line +that was entered using the return key, and one that was +entered by the receipt of a signal. + +.SH THE TERMINAL SIZE + +On most systems the combination of the \f3TIOCGWINSZ\f1 ioctl and the +\f3SIGWINCH\f1 signal is used to maintain an accurate idea of the +terminal size. The terminal size is newly queried every time that +\f3gl_get_line()\f1 is called and whenever a \f3SIGWINCH\f1 signal is +received. +.sp +On the few systems where this mechanism isn't available, at +startup \f3new_GetLine()\f1 first looks for the \f3LINES\f1 +and \f3COLUMNS\f1 environment variables. If these aren't +found, or they contain unusable values, then if a terminal +information database like terminfo or termcap is available, +the default size of the terminal is looked up in this +database. If this too fails to provide the terminal size, a +default size of 80 columns by 24 lines is used. If this +default isn't appropriate for your system, +\f3gl_terminal_size()\f1 can be used to supply a different +fallback. +.sp +The \f3gl_terminal_size()\f1 function allows you to query +the current size of the terminal, and install an alternate +fallback size for cases where the size isn't available. +Beware that the terminal size won't be available if reading +from a pipe or a file, so the default values can be +important even on systems that do support ways of finding +out the terminal size. +.sp +.nf + typedef struct { + int nline; /* The terminal has nline lines */ + int ncolumn; /* The terminal has ncolumn columns */ + } GlTerminalSize; + + GlTerminalSize gl_terminal_size(GetLine *gl, + int def_ncolumn, + int def_nline); +.fi +.sp +This function first updates \f3gl_get_line()\f1's idea of +the terminal size, then records its findings in the return +value. +.sp +The \f3def_ncolumn\f1 and \f3def_nline\f1 specify the +default number of terminal columns and lines to use if the +terminal size can't be determined. + +.SH HIDING WHAT YOU TYPE + +When entering sensitive information, such as passwords, it is best not +to have the text that you are entering echoed on the terminal. +Furthermore, such text should not be recorded in the history list, +since somebody finding your terminal unattended could then recall it, +or somebody snooping through your directories could see it in your +history file. With this in mind, the \f3gl_echo_mode()\f1 +function allows you to toggle on and off the display and archival of +any text that is subsequently entered in calls to \f3gl_get_line()\f1. + +.sp +.nf + int gl_echo_mode(GetLine *gl, int enable); +.fi +.sp + +The \f3enable\f1 argument specifies whether entered text +should be visible or not. If it is \f30\f1, then +subsequently entered lines will not be visible on the +terminal, and will not be recorded in the history list. If +it is \f31\f1, then subsequent input lines will be displayed +as they are entered, and provided that history hasn't been +turned off via a call to \f3gl_toggle_history()\f1, then +they will also be archived in the history list. Finally, if +the \f3enable\f1 argument is \f3-1\f1, then the echoing mode +is left unchanged, which allows you to non-destructively +query the current setting via the return value. In all +cases, the return value of the function is \f30\f1 if +echoing was disabled before the function was called, and +\f31\f1 if it was enabled. +.sp +When echoing is turned off, note that although tab +completion will invisibly complete your prefix as far as +possible, ambiguous completions will not be displayed. + +.SH CALLBACK FUNCTION FACILITIES + +Unless otherwise stated, callback functions, such as tab +completion callbacks and event callbacks should not call any +functions in this module. The following functions, however, +are designed specifically to be used by callback functions. +.sp +Calling the \f3gl_replace_prompt()\f1 function from a +callback tells \f3gl_get_line() to display a different +prompt when the callback returns. It has no effect if called +when \f3gl_get_line()\f1 is not being called. +.sp +.nf + void gl_replace_prompt(GetLine *gl, const char *prompt); +.fi +.sp + +.SH INTERNATIONAL CHARACTER SETS + +Since libtecla version 1.4.0, \f3gl_get_line()\f1 has been 8-bit +clean. This means that all 8-bit characters that are printable in the +user's current locale are now displayed verbatim and included in the +returned input line. Assuming that the calling program correctly +contains a call like the following, +.sp +.nf + setlocale(LC_CTYPE, ""); +.fi +.sp +then the current locale is determined by the first of the environment +variables \f3LC_CTYPE\f1, \f3LC_ALL\f1, and \f3LANG\f1, that is found +to contain a valid locale name. If none of these variables are +defined, or the program neglects to call setlocale, then the default +\f3C\f1 locale is used, which is US 7-bit ASCII. On most unix-like +platforms, you can get a list of valid locales by typing the command: +.sp +.nf + locale -a +.fi +.sp +at the shell prompt. +.sp +.SS "Meta keys and locales" + +Beware that in most locales other than the default C locale, meta +characters become printable, and they are then no longer considered to +match \f3M-c\f1 style key bindings. This allows international +characters to be entered with the compose key without unexpectedly +triggering meta key bindings. You can still invoke meta bindings, +since there are actually two ways to do this. For example the binding +\f3M-c\f1 can also be invoked by pressing the escape key momentarily, +then pressing the \f3c\f1 key, and this will work regardless of +locale. Moreover, many modern terminal emulators, such as gnome's +gnome-terminal's and KDE's konsole terminals, already generate escape +pairs like this when you use the meta key, rather than a real meta +character, and other emulators usually have a way to request this +behavior, so you can continue to use the meta key on most systems. +.sp +For example, although xterm terminal emulators generate real 8-bit +meta characters by default when you use the meta key, they can be +configured to output the equivalent escape pair by setting their +\f3EightBitInput\f1 X resource to \f3False\f1. You can either do this +by placing a line like the following in your \f3~/.Xdefaults\f1 file, +.sp +.nf + XTerm*EightBitInput: False +.sp +.fi +or by starting an xterm with an \f3-xrm '*EightBitInput: False'\f1 +command-line argument. In recent versions of xterm you can toggle this +feature on and off with the \f3"Meta Sends Escape"\f1 option in the +menu that is displayed when you press the left mouse button and the +control key within an xterm window. In CDE, dtterms can be similarly +coerced to generate escape pairs in place of meta characters, by +setting the \f3Dtterm*KshMode\f1 resource to \f3True\f1. +.sp +.SS "Entering international characters" + +If you don't have a keyboard that generates all of the international +characters that you need, there is usually a compose key that will +allow you to enter special characters, or a way to create one. For +example, under X windows on unix-like systems, if your keyboard +doesn't have a compose key, you can designate a redundant key to serve +this purpose with the xmodmap command. For example, on many PC +keyboards there is a microsoft-windows key, which is otherwise useless +under Linux. On my PC the \f3xev\f1 program reports that pressing this +key generates keycode 115, so to turn this key into a compose key, I +do the following: +.sp +.nf + xmodmap -e 'keycode 115 = Multi_key' +.fi +.sp +I can then enter an i with a umlaut over it by typing this key, +followed by \f3"\f1, followed by i. + +.SH THREAD SAFETY + +In a multi-threaded program, you should use the libtecla_r.a version +of the library. This uses reentrant versions of system functions, +where available. Unfortunately neither terminfo nor termcap were +designed to be reentrant, so you can't safely use the functions of the +getline module in multiple threads (you can use the separate +file-expansion and word-completion modules in multiple threads, see +the corresponding man pages for details). However due to the use of +POSIX reentrant functions for looking up home directories etc, it is +safe to use this module from a single thread of a multi-threaded +program, provided that your other threads don't use any termcap or +terminfo functions. + +.SH FILES +.nf +libtecla.a - The tecla library +libtecla.h - The tecla header file. +~/.teclarc - The personal tecla customization file. +.fi + +.SH SEE ALSO +libtecla(3), ef_expand_file(3), cpl_complete_word(3), pca_lookup_file(3) + +.SH AUTHOR +Martin Shepherd (mcs@astro.caltech.edu) |