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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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POSIX_SP..._ADDDUP2(3P) POSIX Programmer's ManualPOSIX_SP..._ADDDUP2(3P)
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.
posix_spawn_file_actions_adddup2 — add dup2 action to spawn file
actions object (ADVANCED REALTIME)
#include <spawn.h>
int posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t
*file_actions, int fildes, int newfildes);
The posix_spawn_file_actions_adddup2() function shall add a
dup2() action 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_actions_addclose(3p).
Upon successful completion, the
posix_spawn_file_actions_adddup2() function shall return zero;
otherwise, an error number shall be returned to indicate the
error.
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 object.
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 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.
The following sections are informative.
None.
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 application has obtained through
explicit actions, or for the three file descriptors 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.
Refer to the RATIONALE section in
posix_spawn_file_actions_addclose(3p).
None.
dup(3p), posix_spawn(3p), posix_spawn_file_actions_addclose(3p),
posix_spawn_file_actions_destroy(3p)
The Base Definitions volume of POSIX.1‐2017, spawn.h(0p)
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications 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.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2017 POSIX_SP..._ADDDUP2(3P)
Pages that refer to this page: spawn.h(0p), posix_spawn(3p), posix_spawn_file_actions_addclose(3p)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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