posix_spawn_file_actions_adddup2(3) [linux man page]

POSIX_SPAWN_FILE_ACTIONS_ADDDUP2(P)			     POSIX Programmer's Manual			       POSIX_SPAWN_FILE_ACTIONS_ADDDUP2(P)

NAME

       posix_spawn_file_actions_adddup2 - add dup2 action to spawn file actions 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() 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() .

RETURN VALUE

       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

       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 asso-
       ciated 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.

RATIONALE

       Refer to the RATIONALE in posix_spawn_file_actions_addclose() .

FUTURE DIRECTIONS

       None.

SEE ALSO

       dup() , posix_spawn() , posix_spawn_file_actions_addclose() , posix_spawn_file_actions_destroy() , posix_spawnp() ,  the  Base  Definitions
       volume of IEEE Std 1003.1-2001, <spawn.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 .

IEEE
/The Open Group						       2003				       POSIX_SPAWN_FILE_ACTIONS_ADDDUP2(P)

POSIX_SPAWN_FILE_ACTIONS_ADDOPEN(3)			   BSD Library Functions Manual 		       POSIX_SPAWN_FILE_ACTIONS_ADDOPEN(3)

NAME

     posix_spawn_file_actions_addopen, posix_spawn_file_actions_adddup2, posix_spawn_file_actions_addclose -- add open, dup2 or close action to
     spawn file actions object

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <spawn.h>

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

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

     int
     posix_spawn_file_actions_addclose(posix_spawn_file_actions_t * file_actions, int fildes);

DESCRIPTION

     These functions add an open, dup2 or close 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() or posix_spawnp() operation in order 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(), specify 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 is as if 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()).

     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.

     The posix_spawn_file_actions_adddup2() function adds a dup2 action to the object referenced by file_actions that causes 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, except that the FD_CLOEXEC flag for newfildes is cleared even
     if fildes is equal to newfildes.  The difference from dup2() is useful for passing a particular file descriptor to a particular child
     process.

     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.

RETURN VALUES

     Upon successful completion, these functions return zero; otherwise, an error number is returned to indicate the error.

ERRORS

     These functions fail if:

     [EBADF]		The value specified by fildes or newfildes is negative.

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

SEE ALSO

     close(2), dup2(2), open(2), posix_spawn(3), posix_spawn_file_actions_destroy(3), posix_spawn_file_actions_init(3), posix_spawnp(3)

STANDARDS

     The posix_spawn_file_actions_addopen(), posix_spawn_file_actions_adddup2() and posix_spawn_file_actions_addclose() functions conform to IEEE
     Std 1003.1-2001 (``POSIX.1''), with the exception of the behavior of posix_spawn_file_actions_adddup2() if fildes is equal to newfildes
     (clearing FD_CLOEXEC).  A future update of the Standard is expected to require this behavior.

HISTORY

     The posix_spawn_file_actions_addopen(), posix_spawn_file_actions_adddup2() and posix_spawn_file_actions_addclose() functions first appeared
     in FreeBSD 8.0.

AUTHORS

     Ed Schouten <ed@FreeBSD.org>

BSD
								    May 9, 2013 							       BSD