.TH GELF_UPDATE_REL 3 2025-09-27 "Libelf" "Libelf Programmer's Manual"

.SH NAME
gelf_update_rel, gelf_update_rela \- copy class\-independent relocation entries into a relocation section

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

.BI "int gelf_update_rel (Elf_Data *" data ", int " ndx ", GElf_Rel  *" src ");"
.BI "int gelf_update_rela(Elf_Data *" data ", int " ndx ", GElf_Rela *" src ");"
.fi

.SH DESCRIPTION
The
.BR gelf_update_rel ()
and
.BR gelf_update_rela ()
functions copy a class\-independent REL or RELA relocation entry from
.IR *src
into the SHT_REL or SHT_RELA section associated with
.I data
at entry index
.IR ndx .

.SH PARAMETERS
.TP
.I data
.B Elf_Data
for a relocation section.  The section must have sh_type
.B SHT_REL
for
.BR gelf_update_rel ()
or
.B SHT_RELA
for
.BR gelf_update_rela ().

.TP
.I ndx
Zero\-based index of the relocation entry within
.IR data .

.TP
.I src
Pointer to the caller\-provided source entry:
.B GElf_Rel
for
.BR gelf_update_rel ()
and
.B GElf_Rela
for
.BR gelf_update_rela ().
.I src
must not be NULL.

For
.B ELFCLASS32
binaries,
.I r_offset
should fit in unsigned 32 bits.
.I r_addend
should fit in signed 32 bits.  The
.B GELF_R_SYM
component of
.I r_info
should fit in 24 bits and the
.B GELF_R_TYPE
component should fit in 8 bits.

.SH RETURN VALUE
On success,
.BR gelf_update_rel ()
and
.BR gelf_update_rela ()
copy
.I src
into
.IR data ,
flag the corresponding section with
.B ELF_F_DIRTY
and return a non-zero value.  On failure, these functions return 0 and set
elf_errno.  If
.I src
is NULL, then 0 is returned without setting elf_errno.

.SH SEE ALSO
.BR gelf_getrel (3),
.BR gelf_getrela (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_rel (),\~gelf_update_rela ()
T}	Thread safety	MT-Safe
.TE

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