NAME
dwarf_get_abbrev
—
retrieve abbreviation
information
LIBRARY
library “libdwarf”
SYNOPSIS
#include
<libdwarf.h>
int
dwarf_get_abbrev
(Dwarf_Debug
dbg, Dwarf_Unsigned offset,
Dwarf_Abbrev *ret_abbrev,
Dwarf_Unsigned *length, Dwarf_Unsigned
*attr_count, Dwarf_Error *err);
DESCRIPTION
Functiondwarf_get_abbrev
()
retrieves information about an abbreviation from the DWARF abbreviations
section, “.debug_abbrev”. Abbreviation information is returned
using an opaque descriptor of type Dwarf_Abbrev. The
returned Dwarf_Abbrev descriptor may then be passed to
the other abbreviation related APIs in the DWARF(3) API to retrieve specific
information about the abbreviation.
Argument dbg should reference a DWARF debug context allocated using dwarf_init(3).
Argument offset should be an offset, relative to the “.debug_abbrev” section, to the start of an abbreviation entry.
Argument ret_abbrev should point to a location that will hold a pointer to the returned Dwarf_Abbrev descriptor.
Argument length should point to a location that will hold the number of bytes used by the abbrevation in the DWARF “.debug_abbrev” section.
Argument attr_count should point to a location that will hold the number of attributes in the abbrevation.
If argument err is not NULL, it will be used to store error information in case of an error.
Memory Management
The memory area used for the Dwarf_Abbrev
descriptor returned in argument ret_abbrev is
allocated by the library “libdwarf”.
Application code should use function
dwarf_dealloc
()
with the allocation type DW_DLA_ABBREV
to free the
memory area when the Dwarf_Abbrev descriptor is no
longer needed.
Application Programming Notes
The last abbreviation entry in a standard DWARF abbreviation section will have a special length value of 1.
RETURN VALUES
Function dwarf_get_abbrev
() returns
DW_DLV_OK
when it succeeds. It returns
DW_DLV_NO_ENTRY
if there is no abbreviation
information at offset offset. In case of an error, it
returns DW_DLV_ERROR
and sets the argument
err.
EXAMPLES
To loop through all the abbreviation information associated with a DWARF debug context, use:
Dwarf_Debug dbg; Dwarf_Abbrev ab; Dwarf_Off aboff; Dwarf_Unsigned length, attr_count; Dwarf_Half tag; Dwarf_Error de; int ret; while ((ret = dwarf_next_cu_header(dbg, NULL, NULL, &aboff, NULL, NULL, &de)) == DW_DLV_OK) { while ((ret = dwarf_get_abbrev(re->dbg, aboff, &ab, &length, &attr_count, &de)) == DW_DLV_OK) { if (length == 1) /* Last entry. */ break; aboff += length; if (dwarf_get_abbrev_tag(ab, &tag, &de) != DW_DLV_OK) { warnx("dwarf_get_abbrev_tag failed: %s", dwarf_errmsg(de)); continue; } if (ret != DW_DLV_OK) warnx("dwarf_get_abbrev: %s", dwarf_errmsg(de)); } if (ret == DW_DLV_ERROR) warnx("dwarf_next_cu_header: %s", dwarf_errmsg(de));
ERRORS
Function dwarf_get_abbrev
() can fail
with:
- [
DW_DLE_ARGUMENT
] - One of the arguments dbg, ret_abbrev, length or attr_count was NULL.
- [
DW_DLE_NO_ENTRY
] - There is no abbreviation information at offset offset.
SEE ALSO
dwarf(3), dwarf_dealloc(3), dwarf_get_abbrev_children_flag(3), dwarf_get_abbrev_code(3), dwarf_get_abbrev_entry(3), dwarf_get_abbrev_tag(3)