NAME

posix_spawnattr_setflags posix_spawnattr_getflags — get or set flags on a posix_spawnattr_t

SYNOPSIS

#include <spawn.h>

int
posix_spawnattr_setflags(posix_spawnattr_t *attr, short flags);

int
posix_spawnattr_getflags(const posix_spawnattr_t *restrict attr, short *restrict flags);

DESCRIPTION

The posix_spawnattr_setflags() function sets the flags on the attributes object referenced by attr.

The posix_spawnattr_getflags() function retrieves the flags on the attributes object referenced by attr.

The argument flags is either 0 or a bitwise OR of one or more of the following flags:

POSIX_SPAWN_RESETIDS

If this bit is set, the child process will inherit the real (rather than the effective) user and group ID of the parent process. NOTE: This flag has no effect when the set-group bit is set on the process image being spawned.

POSIX_SPAWN_SETPGROUP

If this bit is not set, then the child process inherits the parent process group; if it is set, then the child process will behave as if the setpgid(2) function had been called with a pid parameter of 0 and a pgid parameter equal to the value of the spawn-pgroup value of the posix_spawnattr_t, as set by posix_spawnattr_setpgroup(3)

POSIX_SPAWN_SETSIGDEF

Signals set to either be caught or to the default action in the parent process will also be set to the default action in the child process. Signals set to be ignored in the parent process will be ignored in the child. However, if this bit is set, then signals in the spawn-sigdefault value of the posix_spawnattr_t, as set by posix_spawnattr_setsigdefault(3) which are caught or ignored in the parent will instead be reset to their default actions in the child.

POSIX_SPAWN_SETSIGMASK

If this bit is set, then the initial signal mask of the child process will be set to the spawn-sigmask value of the posix_spawnattr_t, as set by posix_spawnattr_setsigmask(3).

POSIX_SPAWN_SETEXEC

Apple Extension: If this bit is set, rather than returning to the caller, posix_spawn(2) and posix_spawnp(2) will behave as a more featureful execve(2).

POSIX_SPAWN_START_SUSPENDED

Apple Extension: If this bit is set, then the child process will be created as if it immediately received a SIGSTOP signal, permitting debuggers, profilers, and other programs to manipulate the process before it begins execution in user space. This permits, for example, obtaining exact instruction counts, or debugging very early in dyld(1). To resume the child process, it must be sent a SIGCONT signal.

POSIX_SPAWN_CLOEXEC_DEFAULT

Apple Extension: If this bit is set, then only file descriptors explicitly created by the file_actions argument are available in the spawned process; all of the other file descriptors are automatically closed in the spawned process.

RETURN VALUES

On success, these functions return 0; on failure they return an error number from <errno.h>. The posix_spawnattr_getflags() function additionally, upon successful completion, makes the value pointed to by the flags argument equal to the spawn-flags attribute of the posix_spawnattr_t.

ERRORS

These functions may fail if:

[EINVAL]

The value specified by attr is invalid.

[EINVAL]

The value of attr is invalid.

SEE ALSO

posix_spawn(2), posix_spawnp(2), posix_spawnattr_init(3), posix_spawnattr_destroy(3), posix_spawnattr_setpgroup(3), posix_spawnattr_setsigdefault(3), posix_spawnattr_setsigmask(3), posix_spawn_file_actions_init(3), setpgid(2), signal(3), execve(2), dyld(1)

STANDARDS

Version 3 of the Single UNIX Specification (“SUSv3”) [SPN]

HISTORY

The posix_spawnattr_setflags() and posix_spawnattr_getflags() function calls appeared in Version 3 of the Single UNIX Specification (“SUSv3”) [SPN].