POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE(3C) Standard C Library Functions

NAME

posix_spawn_file_actions_addclose, posix_spawn_file_actions_addopen -
add close or open action to spawn file actions object

SYNOPSIS

#include <spawn.h>

int posix_spawn_file_actions_addclose(
posix_spawn_file_actions_t *file_actions, int fildes);


int posix_spawn_file_actions_addopen(
posix_spawn_file_actions_t *restrict file_actions, int fildes,
const char *restrict path, int oflag, mode_t mode);

DESCRIPTION

These functions add or delete a close or open 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(3C) or posix_spawn(3C) operation 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(), specifies how the set of open file descriptors in the
calling process is transformed into a set of potentially open file
descriptors for the spawned process. This transformation occurs as
though 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(3C)).


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.


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.

RETURN VALUES

Upon successful completion, these functions return 0. Otherwise, an
error number is returned to indicate the error.

ERRORS

These functions will fail if:

EBADF
The value specified by fildes is negative or greater than or
equal to {OPEN_MAX}.


These functions may fail if:

EINVAL
The value specified by file_actions is invalid.


ENOMEM
Insufficient memory exists to add to the spawn file actions
object.


It is not considered an error for the fildes argument passed to these
functions to specify a file descriptor for which the specified
operation could not be performed at the time of the call. Any such
error will be detected when the associated file actions object is
later used during a posix_spawn() or posix_spawnp() operation.


If a close(2) operation is specified for a file descriptor that is
not open at the time of the call to posix_spawn() or posix_spawnp(),
the close operation will not cause the posix_spawn() or
posix_spawnp() operation to fail.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|MT-Level | MT-Safe |
+--------------------+-------------------+
|Standard | See standards(7). |
+--------------------+-------------------+

SEE ALSO

close(2), dup(2), open(2), posix_spawn(3C),
posix_spawn_file_actions_adddup2(3C),
posix_spawn_file_actions_destroy(3C), attributes(7), standards(7)

February 20, 2009
POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE(3C)