PROLOG         top

       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         top

       posix_spawn_file_actions_adddup2 — add dup2 action to spawn file
       actions object (ADVANCED REALTIME)

SYNOPSIS         top

       #include <spawn.h>

       int posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t
           *file_actions, int fildes, int newfildes);

DESCRIPTION         top

       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

RETURN VALUE         top

       Upon successful completion, the posix_spawn_file_actions_adddup2()
       function shall return zero; otherwise, an error number shall be
       returned to indicate the error.

ERRORS         top

       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

       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.

EXAMPLES         top



       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.

RATIONALE         top

       Refer to the RATIONALE section in



SEE ALSO         top

       dup(3p), posix_spawn(3p), posix_spawn_file_actions_addclose(3p),

       The Base Definitions volume of POSIX.1‐2008, spawn.h(0p)

COPYRIGHT         top

       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 .

       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 .

IEEE/The Open Group                 2013POSIX_SPAWN_FILE_ACTIONS_ADDDUP2(3P)