#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 adds a dup2(3C) 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.
A spawn file actions object is as defined in posix_spawn_file_actions_addclose(3C).
Upon successful completion, the posix_spawn_file_actions_adddup2() function returns 0. Otherwise, an error number is be returned to indicate the error.
The posix_spawn_file_actions_adddup2() function will 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 is not considered an error for the fildes argument passed to posix_spawn_file_actions_adddup2() 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(3C) or posix_spawnp(3C) operation.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| Interface Stability | Standard |
| MT-Level | MT-Safe |
dup2(3C), posix_spawn(3C), posix_spawn_file_actions_addclose(3C), posix_spawn_file_actions_destroy(3C), attributes(5), standards(5)