pthread_attr_setsigmask_np(3) — Linux manual page



NAME         top

       pthread_attr_setsigmask_np, pthread_attr_getsigmask_np - set/get sig‐
       nal mask attribute in thread attributes object

SYNOPSIS         top

       #define _GNU_SOURCE             /* See feature_test_macros(7) */
       #include <pthread.h>

       int pthread_attr_setsigmask_np(pthread_attr_t *attr,
                                      const sigset_t *sigmask);
       int pthread_attr_getsigmask_np(const pthread_attr_t *attr,
                                      sigset_t *sigmask);

       Compile and link with -pthread.

DESCRIPTION         top

       The pthread_attr_setsigmask_np() function sets the signal mask
       attribute of the thread attributes object referred to by attr to the
       value specified in *sigmask.  If sigmask is specified as NULL, then
       any existing signal mask attribute in attr is unset.

       The pthread_attr_getsigmask_np() function returns the signal mask
       attribute of the thread attributes object referred to by attr in the
       buffer pointed to by sigmask.  If the signal mask attribute is
       currently unset, then this function returns the special value
       PTHREAD_ATTR_NO_SIGMASK_NP as its result.

RETURN VALUE         top

       The pthread_attr_setsigmask_np() function returns 0 on success, or a
       nonzero error number on failure.

       the pthread_attr_getsigmask_np() function returns either 0 or
       PTHREAD_ATTR_NO_SIGMASK_NP.  When 0 is returned, the signal mask
       attribute is returned via sigmask.  A return value of
       PTHREAD_ATTR_NO_SIGMASK_NP indicates that the signal mask attribute
       is not set in attr.

       On error, these functions return a positive error number.

ERRORS         top

       ENOMEM (pthread_attr_setsigmask_np()) Could not allocate memory.

VERSIONS         top

       These functions are provided by glibc since version 2.32.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface                      Attribute     Value   │
       │pthread_attr_setsigmask_np(),  │ Thread safety │ MT-Safe │
       │pthread_attr_getsigmask_np()   │               │         │

CONFORMING TO         top

       These functions are nonstandard GNU extensions; hence the suffix
       "_np" (nonportable) in the names.

NOTES         top

       The signal mask attribute determines the signal mask that will be
       assigned to a thread created using the thread attributes object attr.
       If this attribute is not set, then a thread created using attr will
       inherit a copy of the creating thread's signal mask.

       For more details on signal masks, see sigprocmask(2).  For a
       description of a set of macros that can be used to manipulate and
       inspect signals sets, see sigsetops(3).

       In the absence of pthread_attr_setsigmask_np() it is possible to
       create a thread with a desired signal mask as follows:

       • The creating thread uses pthread_sigmask(3) to save its current
         signal mask and set its mask to block all signals.

       • The new thread is then created using pthread_create(); the new
         thread will inherit the creating thread's signal mask.

       • The new thread sets its signal mask to the desired value using

       • The creating thread restores its signal mask to the original value.

       Following the above steps, there is no possibility for the new thread
       to receive a signal before it has adjusted its signal mask to the
       desired value.

SEE ALSO         top

       sigprocmask(2), pthread_attr_init(3), pthread_sigmask(3),
       pthreads(7), signals(7)

COLOPHON         top

       This page is part of release 5.09 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

Linux                            2020-11-01    PTHREAD_ATTR_SETSIGMASK_NP(3)

Pages that refer to this page: pthread_attr_destroy(3)pthread_attr_init(3)pthread_sigmask(3)