NAME

gelf_getsym, gelf_update_sym — read and update symbol information

LIBRARY

library “libelf”

SYNOPSIS

#include <gelf.h>

GElf_Sym *
gelf_getsym(Elf_Data *data, int ndx, GElf_Sym *sym);

int
gelf_update_sym(Elf_Data *data, int ndx, GElf_Sym *sym);

DESCRIPTION

These convenience functions are used to retrieve and update class-dependent Elf32_Sym and Elf64_Sym structures in an ELF object.

Argument data is an Elf_Data descriptor associated with a section of type SHT_SYMTAB, SHT_DYNSYM or SHT_GNU_versym. Argument ndx is the index of the symbol being retrieved or updated. The class-independent GElf_Sym structure is described in gelf(3).

Function gelf_getsym() retrieves class-dependent symbol information at index ndx in data buffer data and copies it to the destination pointed to by argument sym after translation to class-independent form.

Function gelf_update_sym() converts the class-independent symbol information pointed to by argument sym to class-dependent form, and writes it to the symbol entry at index ndx in the data buffer described by argument data. Function gelf_update_sym() signals an error if any of the values in the class-independent representation exceeds the representable limits of the target type.

RETURN VALUES

Function gelf_getsym() returns the value of argument sym if successful, or NULL in case of an error. Function gelf_update_sym() returns a non-zero value if successful, or zero in case of an error.

ERRORS

These functions may fail with the following errors:

[ELF_E_ARGUMENT]: Arguments data or sym were NULL.
[ELF_E_ARGUMENT]: Argument ndx was less than zero or larger than the number of symbols in the data descriptor.
[ELF_E_ARGUMENT]: Data descriptor data was not associated with a section containing symbol information.
[ELF_E_RANGE]: A value was not representable in the target type.
[ELF_E_VERSION]: The Elf_Data descriptor denoted by argument data is associated with an ELF object with an unsupported version.