.\" Copyright 2026 The FreeBSD Foundation
.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.\" This documentation was written by
.\" Konstantin Belousov <kib@FreeBSD.org> under sponsorship
.\" from the FreeBSD Foundation.
.\"
.Dd January 25, 2026
.Dt POSIX_SPAWNATTR_GETEXECFD_NP 3
.Os
.Sh NAME
.Nm posix_spawnattr_getexecfd_np ,
.Nm posix_spawnattr_setexecfd_np
.Nd "get and set the spawn-execfd attribute of a spawn attributes object"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In spawn.h
.Ft int
.Fo posix_spawnattr_getexecfd_np
.Fa "const posix_spawnattr_t *restrict attr"
.Fa "int *restrict fdp"
.Fc
.Ft int
.Fo posix_spawnattr_setexecfd_np
.Fa "posix_spawnattr_t *attr"
.Fa "int fd"
.Fc
.Sh DESCRIPTION
The
.Fn posix_spawnattr_getexecfd_np
function obtains the value of the spawn-execfd attribute from the
attributes object referenced by
.Fa attr .
.Pp
The
.Fn posix_spawnattr_setexecfd_np
function sets the spawn-execfd attribute in an initialized attributes
object referenced by
.Fa attr .
.Pp
The spawn-execfd attribute provides the file descriptor that is used
to execute new image in the spawned process by the
.Xr posix_spawn 3
family of functions.
If the attribute is set to a value other then \-1, it must be a valid
file descriptor which does not have the
.Va O_CLOFORK
flag set.
Then,
.Fn posix_spawn
executes the executable image referenced by the file descriptor in the
newly created process, using the
.Xr fexecve 2
system call.
In this case, the
.Fa path
argument to
.Fn posix_spawn
is ignored.
.Pp
The default value for the spawn-execfd attribute is \-1, which
means that the executed image is specified by the
.Fa path
argument to
.Fn posix_spawn .
.Sh RETURN VALUES
The
.Fn posix_spawnattr_getexecfd_np
and
.Fn posix_spawnattr_setexecfd_np
functions return zero.
.Sh SEE ALSO
.Xr posix_spawn 3 ,
.Xr posix_spawnattr_destroy 3 ,
.Xr posix_spawnattr_init 3 ,
.Xr posix_spawnp 3
.Sh STANDARDS
The
.Fn posix_spawnattr_getexecfd_np
and
.Fn posix_spawnattr_setexecfd_np
are
.Fx
extensions that first appeared in
.Fx 16.0 .