HP-UX Reference (11i v2 07/12) - 3 Library Functions N-Z (vol 7)

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pthread_sigmask(3T) pthread_sigmask(3T)

(Pthread Library)

NAME

pthread_sigmask() - examine/change signal mask of calling thread

SYNOPSIS

#include <pthread.h>

int pthread_sigmask(

int how,

const sigset_t *set,

sigset_t *oset

);

PARAMETERS

how This parameter deﬁnes how the signal mask of the calling thread will be changed.

set Pointer to the set of signals that will be used to change the currently blocked signal set.

oset Pointer to where the previous signal mask will be returned.

DESCRIPTION

pthread_sigmask()

allows the calling thread to examine and/or change its signal mask.

Unless it is a null pointer, the argument set points to a set of signals which are to be used to change the

currently blocked signal set.

The argument how indicates how the set is changed. The legal values are:

SIG_BLOCK The resulting set is the union of the current set and the signal set pointed to by

set.

SIG_UNBLOCK The resulting set is the intersection of the current set and the complement of the

signal set pointed to by set.

SIG_SETMASK The resulting set is the signal set pointed to by set.

If the argument oset is not a null pointer, the previous signal mask is returned in oset. If set is a null

pointer, the value of the argument how is insigniﬁcant and the thread’s signal mask is unchanged; thus, the

call can be used to inquire about currently blocked signals.

If there any pending unblocked signals after the call to

pthread_sigmask()

, at least one of those sig-

nals is delivered before the call to

pthread_sigmask()

returns.

It is impossible to block the

SIGKILL or SIGSTOP signal. This is enforced by the system without causing

an error to be indicated.

The thread’s signal mask is not changed if pthread_sigmask()

fails for any reason.

RETURN VALUE

Upon successful completion,

pthread_sigmask()

returns zero. Otherwise, an error number is

returned to indicate the error (the

errno variable is not set).

ERRORS

If any of the following occur, the pthread_sigmask() function returns the corresponding error

number:

[EINVAL] how contains an invalid value.

[EFAULT] set or oset points to an invalid address. The reliable detection of this error is imple-

mentation dependent.

AUTHOR

pthread_sigmask() was derived from the IEEE POSIX P1003.1c standard.