-
-
Save enebo/89b074d2639f1f24cb80387262ff298e to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
POSIX_SPAWN_FILE_ACTIONS_ADPOSIX(ProgrammePOsIXaSPaWN_FILE_ACTIONS_ADDDUP2(3P) | |
PROLOG | |
This manual page is part of the POSIX Programmer's Manual. The Linux | |
implementation of this interface may differ (consult the corresponding | |
Linux manual page for details of Linux behavior), or the interface may | |
not be implemented on Linux. | |
NAME | |
posix_spawn_file_actions_adddup2 — add dup2 action to spawn file ac‐ | |
tions object (ADVANCED REALTIME) | |
SYNOPSIS | |
#include <spawn.h> | |
int posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t | |
*file_actions, int fildes, int newfildes); | |
DESCRIPTION | |
The posix_spawn_file_actions_adddup2() function shall add a dup2() ac‐ | |
tion to the object referenced by file_actions that shall cause 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. | |
A spawn file actions object is as defined in posix_spawn_file_ac‐ | |
tions_addclose(). | |
RETURN VALUE | |
Upon successful completion, the posix_spawn_file_actions_adddup2() | |
function shall return zero; otherwise, an error number shall be re‐ | |
turned to indicate the error. | |
ERRORS | |
The posix_spawn_file_actions_adddup2() function shall fail if: | |
EBADF The value specified by fildes or newfildes is negative or | |
greater than or equal to {OPEN_MAX}. | |
ENOMEM Insufficient memory exists to add to the spawn file actions ob‐ | |
ject. | |
The posix_spawn_file_actions_adddup2() function may fail if: | |
EINVAL The value specified by file_actions is invalid. | |
It shall not be considered an error for the fildes argument passed to | |
the posix_spawn_file_actions_adddup2() function to specify a file de‐ | |
scriptor for which the specified operation could not be performed at | |
the time of the call. Any such error will be detected when the associ‐ | |
ated file actions object is later used during a posix_spawn() or | |
posix_spawnp() operation. | |
The following sections are informative. | |
EXAMPLES | |
None. | |
APPLICATION USAGE | |
The posix_spawn_file_actions_adddup2() function is part of the Spawn | |
option and need not be provided on all implementations. | |
Implementations may use file descriptors that must be inherited into | |
child processes for the child process to remain conforming, such as for | |
message catalog or tracing purposes. Therefore, an application that | |
calls posix_spawn_file_actions_adddup2() with an arbitrary integer for | |
newfildes risks non-conforming behavior, and this function can only | |
portably be used to overwrite file descriptor values that the applica‐ | |
tion has obtained through explicit actions, or for the three file de‐ | |
scriptors corresponding to the standard file streams. In order to avoid | |
a race condition of leaking an unintended file descriptor into a child | |
process, an application should consider opening all file descriptors | |
with the FD_CLOEXEC bit set unless the file descriptor is intended to | |
be inherited across exec. | |
RATIONALE | |
Refer to the RATIONALE section in posix_spawn_file_actions_addclose(). | |
FUTURE DIRECTIONS | |
None. | |
SEE ALSO | |
dup(), posix_spawn(), posix_spawn_file_actions_addclose(), | |
posix_spawn_file_actions_destroy() | |
The Base Definitions volume of POSIX.1‐2017, <spawn.h> | |
COPYRIGHT | |
Portions of this text are reprinted and reproduced in electronic form | |
from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐ | |
table Operating System Interface (POSIX), The Open Group Base Specifi‐ | |
cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of | |
Electrical and Electronics Engineers, Inc and The Open Group. In the | |
event of any discrepancy between this version and the original IEEE and | |
The Open Group Standard, the original IEEE and The Open Group Standard | |
is the referee document. The original Standard can be obtained online | |
at http://www.opengroup.org/unix/online.html . | |
Any typographical or formatting errors that appear in this page are | |
most likely to have been introduced during the conversion of the source | |
files to man page format. To report such errors, see https://www.ker‐ | |
nel.org/doc/man-pages/reporting_bugs.html . | |
IEEE/The Open Group 2017 POSIX_SPAWN_FILE_ACTIONS_ADDDUP2(3P) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment