GELF_UPDATE_SYMSHNDX(3)	   Libelf Programmer's Manual	 GELF_UPDATE_SYMSHNDX(3)

NAME
     gelf_update_symshndx  - Update class-independent symbol information and ex-
     tended section index in symbol table


SYNOPSIS
     #include <gelf.h>

     int gelf_update_symshndx (Elf_Data *symdata, Elf_Data *shndxdata, int ndx, GElf_Sym *sym, Elf32_Word xshndx);


DESCRIPTION
     This function  updates  symdata  and  shndxdata,  at  index  ndx  with  the
     class-independent symbol information from sym and the section index xshndx.
     symdata  should be an Elf_Data pointer for an SHT_SYMTAB or SHT_DYNSYM sec-
     tion and shndxdata should be an Elf_Data pointer  for  an	SHT_SYMTAB_SHNDX
     section.

     The number of symbols in the symbol table can be calculated by dividing the
     size  of  symdata by the size of a symbol table entry.  The size of symdata
     can be obtained from symdata->d_size  or  from  the  corresponding	 section
     header's  sh_size.	  The  size of a symbol table entry can be obtained from
     gelf_fsize() with ELF_T_SYM or  from  the	corresponding  section	header's
     sh_entsize.

     A	SHT_SYMTAB_SHNDX  section  is present in ELF binaries when the number of
     sections is too large to be represented as an unsigned  16-bit  value.   In
     this case the st_shndx field of a GElf_Sym will be set to SHN_XINDEX to in-
     dicate that the symbol's section index can be found in the SHT_SYMTAB_SHNDX
     section.  shndxdata for this section can be acquired using elf_scnshndx(3),
     elf_getscn(3), and elf_getdata(3).	 The number of entries in shndxdata must
     be	 equal to the number of entries in symdata.  Entry ndx in shndxdata cor-
     responds to entry ndx in symdata.


PARAMETERS
     symdata
	    Pointer to Elf_Data for a section with type SHT_SYMTAB  or	SHT_DYN-
	    SYM.


     shndxdata
	    Pointer  to	 Elf_Data  for	a  section  with  type SHT_SYMTAB_SHNDX.
	    shndxdata may be NULL.  If shndxdata is NULL, then	xshndx	must  be
	    zero.


     ndx    Zero-based	index of the symbol table entry and extended section in-
	    dex entry to be updated.


     sym    Pointer to a caller-provided symbol table entry.  For ELFCLASS32 bi-
	    naries, st_value and st_size should be able to fit	within	unsigned
	    32-bit values.  sym must not be NULL.


     xshndx
	    Updated  extended  section	index  entry  to be associated with sym.
	    Must be zero if shndxdata is NULL.	If sym->st_shndx is not SHN_XIN-
	    DEX then xshndx should be SHN_UNDEF.


RETURN VALUE
     On success, a non-zero value is returned and the entries at  index	 ndx  in
     symdata  and  shndxdata  (if not NULL) are updated with sym and xshndx, re-
     spectively.  The sections associated with symdata and shndxdata are flagged
     with ELF_F_DIRTY.	On failure, zero is returned, elf_errno is set.	 If  sym
     is NULL, then NULL is returned without setting elf_errno.


SEE ALSO
     elf_getdata(3),  elf_getscn(3),  elf_scnshndx(3),	gelf_fsize(3), gelf_get-
     symshndx(3), gelf_update_sym(3), libelf(3), elf(5)


ATTRIBUTES
     allbox; lbx lb lb l l l.  Interface Attribute Value T{
     gelf_update_symshndx() T}	 Thread safety	MT-Safe


REPORTING BUGS
     Report   bugs   to	  <elfutils-devel@sourceware.org>   or	 https://source-
     ware.org/bugzilla/.

Libelf				   2025-12-30		 GELF_UPDATE_SYMSHNDX(3)