.TH GELF_UPDATE_EHDR 3 2025-09-17 "Libelf" "Libelf Programmer's Manual"

.SH NAME
gelf_update_ehdr \- copy a class\-independent ELF header into an ELF descriptor

.SH SYNOPSIS
.nf
.B #include <gelf.h>

.BI "int gelf_update_ehdr(Elf *" elf ", GElf_Ehdr *" src ");"
.fi

.SH DESCRIPTION
.BR gelf_update_ehdr ()
copies the class\-independent ELF header from the structure pointed to by
.I src
into the ELF descriptor
.I elf .
The header is translated as necessary to match the class (
.B ELFCLASS32
or
.BR ELFCLASS64 )
of the underlying object.

If
.I elf
has class
.B ELFCLASS32
then
.BR e_entry ,
.B e_phoff
and
.B e_shoff
must be expressible as 32-bit values.  This function also marks the Ehdr
dirty (see
.BR elf_flagehdr ()).

.SH PARAMETERS
.TP
.I elf
Pointer to an ELF descriptor of kind
.BR ELF_K_ELF .

.TP
.I src
Pointer to a
.B GElf_Ehdr
structure that holds the caller’s desired header contents. Must not be NULL.

.SH RETURN VALUE
On success,
.BR gelf_update_ehdr ()
returns a non-zero value.  On failure, it returns 0 and sets elf_errno.  If
.I elf
is NULL, then 0 is returned without setting elf_errno.

.SH SEE ALSO
.BR gelf_getehdr (3),
.BR gelf_newehdr (3),
.BR elf_flagehdr (3),
.BR libelf (3),
.BR elf (5)

.SH ATTRIBUTES
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.na
.nh
.BR gelf_update_ehdr ()
T}	Thread safety	MT-Safe
.TE

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