DWARF_GET_ABBREV_ENTRY(3)

DWARF_GET_ABBREV_ENTRY(3) | Library Functions Manual | DWARF_GET_ABBREV_ENTRY(3)

# 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.

# 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.

# EXAMPLE

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));

# SEE ALSO

dwarf(3), dwarf_get_abbrev(3)

April 02, 2011 | NetBSD 8.0