NAME

dwarf_get_abbrev_entry — retrieve attribute information from an abbreviation descriptor

LIBRARY

DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

#include <libdwarf.h>

int
dwarf_get_abbrev_entry(Dwarf_Abbrev abbrev, Dwarf_Signed ndx, Dwarf_Half *code, Dwarf_Signed *form, Dwarf_Off *offset, Dwarf_Error *err);

DESCRIPTION

Function dwarf_get_abbrev_entry() retrieves attribute information from a DWARF abbreviation descriptor.

Argument abbrev should be a valid abbreviation descriptor, as returned by function dwarf_get_abbrev(3).

Argument ndx specifies the 0-based index of the attribute. The total count of the attributes contained in the abbreviation entry can be retrieved using the function dwarf_get_abbrev(3).

Argument code should point to a location which will hold a returned attribute code.

Argument form should point to a location which will hold the returned form of the attribute.

Argument offset should point to a location which will hold a returned offset, relative to the “.debug_abbrev” section, for the specified attribute.

If argument err is not NULL, it will be used to return an error descriptor in case of an error.

RETURN VALUES

Function dwarf_get_abbrev_entry() returns DW_DLV_OK when it succeeds. It returns DW_DLV_NO_ENTRY if the attribute index specified by argument ndx is out of range. In case of an error, it returns DW_DLV_ERROR and sets the argument err.

EXAMPLES

To loop through all the attribute entries contained in the abbreviation section, use:

Dwarf_Debug dbg;
Dwarf_Abbrev ab;
Dwarf_Off aboff, atoff;
Dwarf_Signed form;
Dwarf_Half attr;
Dwarf_Unsigned length, attr_count;
Dwarf_Error de;
int i, ret;

/* ...allocate 'dbg' using dwarf_init(3) ... */

while ((ret = dwarf_next_cu_header(dbg, NULL, NULL, &aboff,
    NULL, NULL, &de)) ==  DW_DLV_OK) {
	while ((ret = dwarf_get_abbrev(dbg, aboff, &ab, &length,
	    &attr_count, &de)) == DW_DLV_OK) {
		if (length == 1)	/* Last entry. */
			break;
		aboff += length;
		for (i = 0; (Dwarf_Unsigned) i < attr_count; i++) {
			if (dwarf_get_abbrev_entry(ab, i,
			    &attr, &form, &atoff, &de) != DW_DLV_OK) {
				warnx("dwarf_get_abbrev_entry failed:"
				    " %s", dwarf_errmsg(de));
				continue;
			}
			/* .. use the retrieved information ... */
		}
	}

	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_entry() can fail with:

[DW_DLE_ARGUMENT]: One of the arguments abbrev, code, form or offset was NULL.
[DW_DLE_NO_ENTRY]: The attribute index specified by argument ndx was out of range.