posix_spawn_file_actions_addclose
extern int posix_spawn_file_actions_addclose(
posix_spawn_file_actions_addclose(&fileActions, STDOUT_FILENO);
posix_spawn_file_actions_addclose(&fileActions, STDERR_FILENO);
posix_spawn_file_actions_addclose(&fileActions, pipes[i]);
posix_spawn_file_actions_addclose(&fileActions, socket);
errno = posix_spawn_file_actions_addclose(&fdops, out[readIdx]);
errno = posix_spawn_file_actions_addclose(&fdops, err[readIdx]);