POSIX_SPAWN_FILE_ACTI... BSD Library Functions Manual POSIX_SPAWN_FILE_ACTI...NAME
posix_spawn_file_actions_addopen, posix_spawn_file_actions_adddup2,
posix_spawn_file_actions_addclose — add open, dup2 or close action to
spawn file actions object
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <spawn.h>
int
posix_spawn_file_actions_addopen(posix_spawn_file_actions_t * file_actions,
int fildes, const char *restrict path, int oflag, mode_t mode);
int
posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t * file_actions,
int fildes, int newfildes);
int
posix_spawn_file_actions_addclose(posix_spawn_file_actions_t * file_actions,
int fildes);
DESCRIPTION
These functions add an open, dup2 or close action to a spawn file actions
object.
A spawn file actions object is of type posix_spawn_file_actions_t
(defined in <spawn.h>) and is used to specify a series of actions to be
performed by a posix_spawn() or posix_spawnp() operation in order to
arrive at the set of open file descriptors for the child process given
the set of open file descriptors of the parent.
A spawn file actions object, when passed to posix_spawn() or
posix_spawnp(), specify how the set of open file descriptors in the call‐
ing process is transformed into a set of potentially open file descrip‐
tors for the spawned process. This transformation is as if the specified
sequence of actions was performed exactly once, in the context of the
spawned process (prior to execution of the new process image), in the
order in which the actions were added to the object; additionally, when
the new process image is executed, any file descriptor (from this new
set) which has its FD_CLOEXEC flag set is closed (see posix_spawn()).
The posix_spawn_file_actions_addopen() function adds an open action to
the object referenced by file_actions that causes the file named by path
to be opened (as if
open(path, oflag, mode)
had been called, and the returned file descriptor, if not fildes, had
been changed to fildes) when a new process is spawned using this file
actions object. If fildes was already an open file descriptor, it is
closed before the new file is opened.
The string described by path is copied by the
posix_spawn_file_actions_addopen() function.
The posix_spawn_file_actions_adddup2() function adds a dup2 action to the
object referenced by file_actions that causes the file descriptor fildes
to be duplicated as newfildes (as if
dup2(fildes, newfildes)
had been called) when a new process is spawned using this file actions
object.
The posix_spawn_file_actions_addclose() function adds a close action to
the object referenced by file_actions that causes the file descriptor
fildes to be closed (as if
close(fildes)
had been called) when a new process is spawned using this file actions
object.
RETURN VALUES
Upon successful completion, these functions return zero; otherwise, an
error number is returned to indicate the error.
ERRORS
These functions fail if:
[EINVAL] The value specified by fildes or newfildes is nega‐
tive.
[ENOMEM] Insufficient memory exists to add to the spawn file
actions object.
SEE ALSOclose(2), dup2(2), open(2), posix_spawn(3),
posix_spawn_file_actions_destroy(3), posix_spawn_file_actions_init(3),
posix_spawnp(3)STANDARDS
The posix_spawn_file_actions_addopen(),
posix_spawn_file_actions_adddup2() and
posix_spawn_file_actions_addclose() functions conform to IEEE Std
1003.1-2001 (“POSIX.1”).
HISTORY
The posix_spawn_file_actions_addopen(),
posix_spawn_file_actions_adddup2() and
posix_spawn_file_actions_addclose() functions first appeared in
FreeBSD 8.0 and imported for NetBSD 6.
AUTHORS
Ed Schouten ⟨ed@FreeBSD.org⟩
BSD December 20, 2011 BSD
