.\" Copyright (c) 2011 Kai Wang
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.\" $Id: dwarf_get_globals.3 2071 2011-10-27 03:20:00Z jkoshy $
.\"
.Dd April 2, 2011
.Os
.Dt DWARF_GET_GLOBALS 3
.Sh NAME
.Nm dwarf_get_globals ,
.Nm dwarf_global_cu_offset ,
.Nm dwarf_global_die_offset ,
.Nm dwarf_global_name_offsets ,
.Nm dwarf_globname
.Nd retrieve information about global objects
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_get_globals
.Fa "Dwarf_Debug dbg"
.Fa "Dwarf_Global **globals"
.Fa "Dwarf_Signed *nglobals"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_global_cu_offset
.Fa "Dwarf_Global global"
.Fa "Dwarf_Off *cu_offset"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_global_die_offset
.Fa "Dwarf_Global global"
.Fa "Dwarf_Off *die_offset"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_global_name_offsets
.Fa "Dwarf_Global global"
.Fa "char **name"
.Fa "Dwarf_Off *die_offset"
.Fa "Dwarf_Off *cu_die_offset"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_globname
.Fa "Dwarf_Global global"
.Fa "char **name"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
These functions retrieve information about global symbols from the
lookup tables in the
.Dq ".debug_pubnames"
DWARF section.
Information about these global symbols is returned using opaque descriptors
of type
.Vt Dwarf_Global .
Applications need to use the functions described below to retrieve the
name and the offsets for these descriptors.
.Pp
Function
.Fn dwarf_get_globals
retrieves descriptors for all the global symbols associated with the
DWARF debug context specified by argument
.Ar dbg .
The argument
.Ar globals
should point to a location that will be set to a pointer to an array
of
.Vt Dwarf_Global
descriptors.
The argument
.Ar nglobals
should point to a location that will be set to the number of
descriptors returned.
.Pp
Function
.Fn dwarf_global_cu_offset
returns the section-relative offset, relative to the
.Dq ".debug_info"
section, of the compilation unit that contains the debugging
information entry associated with the argument
.Ar global .
Argument
.Ar cu_offset
should point to a location that will hold the returned offset.
.Pp
Function
.Fn dwarf_global_die_offset
retrieves the section-relative offset, relative to the
.Dq ".debug_info"
section, of the debugging information entry associated with the
argument
.Ar global ,
and stores it into the location pointed to by the argument
.Ar die_offset .
.Pp
Function
.Fn dwarf_global_name_offsets
retrieves the name and the offsets for the debugging information
entry for argument
.Ar global .
Argument
.Ar name
should point to a location which will be set to a pointer to a
NUL-terminated string containing the name of the associated debugging
information entry.
Argument
.Ar die_offset
should point to a location which will be set to a section-relative
offset, relative to the
.Dq ".debug_info"
section, of the associated debugging information entry.
Argument
.Ar cu_die_offset
should point to a location which will be set to a
section-relative offset, relative to the
.Dq ".debug_info"
section, of the first debugging information entry in
the compilation unit associated with argument
.Ar global .
.Pp
Function
.Fn dwarf_globname
sets the location pointed to by argument
.Ar name
to a pointer to a NUL-terminated string holding the name of the
debugging information entry associated with the argument
.Ar global .
.Ss Memory Management
The memory area used for the array of
.Vt Dwarf_Global
descriptors returned in argument
.Ar globals
by function
.Fn dwarf_get_globals
is owned by the
.Lb libdwarf .
Application code should not attempt to directly free this pointer.
Portable code should instead use the function
.Xr dwarf_globals_dealloc 3
to indicate that the memory area may be freed.
.Pp
The memory area used for the string returned in the
.Ar name
argument to functions
.Fn dwarf_globname
and
.Fn dwarf_global_name_offsets
is owned by the
.Lb libdwarf .
Portable code should use the
.Xr dwarf_dealloc 3
function to indicate that the memory area may be freed.
.Ss Error Returns
If argument
.Ar err
is not NULL, these functions will use it to store error information,
in case of an error.
.Sh RETURN VALUES
On success, these functions returns
.Dv DW_DLV_OK .
In case of an error, they return
.Dv DW_DLV_ERROR
and set the argument
.Ar err .
.Sh ERRORS
These functions may fail with the following errors:
.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
.It Bq Er DW_DLE_ARGUMENT
One of the arguments
.Va cu_die_offset ,
.Va cu_offset ,
.Va dbg ,
.Va die_offset ,
.Va global ,
.Va globals ,
.Va name ,
or
.Va nglobals
was NULL.
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_dealloc 3 ,
.Xr dwarf_get_cu_die_offset_given_cu_header_offset 3 ,
.Xr dwarf_globals_dealloc 3