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.

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

       GNU; hence the suffix "_np" (nonportable) in the names.

HISTORY

       glibc 2.32.

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)