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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
POSIX_SPAWN_FILE_ACTIONS_ADDDUP2(3P)rammer'sXManual_FILE_ACTIONS_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.1‐2008, spawn.h(0p)
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/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 2013POSIX_SPAWN_FILE_ACTIONS_ADDDUP2(3P)
Pages that refer to this page: spawn.h(0p), posix_spawn(3p), posix_spawn_file_actions_addclose(3p)