NAME

       pthread_attr_setsigmask_np,  pthread_attr_getsigmask_np - set/get signal mask attribute in
       thread attributes object

LIBRARY

       POSIX threads library (libpthread, -lpthread)

SYNOPSIS

       #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);

DESCRIPTION

       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

       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

       ENOMEM (pthread_attr_setsigmask_np()) Could not allocate memory.

VERSIONS

       These functions are provided since glibc 2.32.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌───────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                      │ Attribute     │ Value   │
       ├───────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │pthread_attr_setsigmask_np(), pthread_attr_getsigmask_np()     │ Thread safety │ MT-Safe │
       └───────────────────────────────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

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

NOTES

       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 signal 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 pthread_sigmask(3).

       •  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

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