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.\" Copyright (c) 2011 Kai Wang
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $Id: dwarf_get_str.3 2071 2011-10-27 03:20:00Z jkoshy $
.\"
.Dd April 3, 2011
.Os
.Dt DWARF_GET_STR 3
.Sh NAME
.Nm dwarf_get_str
.Nd retrieve a string from the DWARF string section
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_get_str
.Fa "Dwarf_Debug dbg"
.Fa "Dwarf_Off offset"
.Fa "char **string"
.Fa "Dwarf_Signed *len"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
Function
.Fn dwarf_get_str
retrieves a NUL-terminated string from the DWARF string section
.Dq ".debug_str" .
.Pp
Argument
.Ar dbg
should reference a DWARF debug context allocated using
.Xr dwarf_init 3 .
.Pp
Argument
.Ar offset
should be an offset, relative to the
.Dq ".debug_str"
section, specifying the start of the desired string.
.Pp
Argument
.Ar string
should point to a location which will hold a returned
pointer to a NUL-terminated string.
.Pp
Argument
.Ar len
should point to a location which will hold the length
of the returned string.
The returned length does not include the space needed for
the NUL-terminator.
.Pp
If argument
.Ar err
is not NULL, it will be used to store error information in case of an
error.
.Sh RETURN VALUES
Function
.Fn dwarf_get_str
returns
.Dv DW_DLV_OK
when it succeeds.
It returns
.Dv DW_DLV_NO_ENTRY
if there is no
.Dq ".debug_str"
section associated with the specified debugging context,
or if the provided offset
.Ar offset
is at the very end of
.Dq ".debug_str"
section.
In case of an error, it returns
.Dv DW_DLV_ERROR
and sets the argument
.Ar err .
.Sh ERRORS
Function
.Fn dwarf_get_str
can fail with:
.Bl -tag -width ".Bq Er DW_DLE_NO_ENTRY"
.It Bq Er DW_DLE_ARGUMENT
One of the arguments
.Ar dbg ,
.Ar string
or
.Ar len
was NULL.
.It Bq Er DW_DLE_ARGUMENT
Argument
.Ar offset
was out of range.
.It Bq Er DW_DLE_NO_ENTRY
The debugging context
.Ar dbg
did not contain a
.Dq ".debug_str"
string section.
.It Bq Er DW_DLE_NO_ENTRY
Argument
.Ar offset
was at the very end of the
.Dq ".debug_str"
section.
.El
.Sh EXAMPLE
To retrieve all the strings in the DWARF string section, use:
.Bd -literal -offset indent
Dwarf_Debug dbg;
Dwarf_Off offset;
Dwarf_Signed len;
Dwarf_Error de;
char *str;
int ret
offset = 0;
while ((ret = dwarf_get_str(dbg, offset, &str, &len, &de)) ==
DW_DLV_OK) {
/* .. Use the retrieved string. .. */
offset += len + 1; /* Account for the terminating NUL. */
}
if (ret == DW_DLV_ERROR)
warnx("dwarf_get_str: %s", dwarf_errmsg(de));
.Ed
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_init 3
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