.\"	$OpenBSD: elf_aux_info.3,v 1.1 2024/07/14 09:48:48 jca Exp $
.\"
.\" Origin: FreeBSD auxv.3
.\"
.\" Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
.\"
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.Dd $Mdocdate: July 14 2024 $
.Dt ELF_AUX_INFO 3
.Os
.Sh NAME
.Nm elf_aux_info
.Nd extract data from the elf auxiliary vector of the current process
.Sh SYNOPSIS
.In sys/auxv.h
.Ft int
.Fn elf_aux_info "int aux" "void *buf" "int buflen"
.Sh DESCRIPTION
The
.Fn elf_aux_info
function retrieves the auxiliary info vector requested in
.Va aux .
The information is stored into the provided buffer if it will fit.
The following values can be requested (corresponding buffer sizes are
specified in parenthesis):
.Bl -tag -width AT_HWCAP2
.It AT_HWCAP
CPU / hardware feature flags
.Dv (sizeof(unsigned long)) .
.It AT_HWCAP2
CPU / hardware feature flags
.Dv (sizeof(unsigned long)) .
.It AT_PAGESZ
Page size in bytes
.Dv (sizeof(int)) .
.El
.Sh RETURN VALUES
Returns zero on success, or an error number on failure.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er EINVAL
An unknown item was requested.
.It Bq Er EINVAL
The provided buffer was not the right size for the requested item.
.It Bq Er ENOENT
The requested item is not available.
.El
.Sh HISTORY
The
.Fn elf_aux_info
function appeared in
.Fx 12.0
and was first available in
.Ox 7.6 .