pthread_attr_setsigmask_np, pthread_attr_getsigmask_np - set/get signal mask attribute in thread attributes object
#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.
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 is specified as NULL, then any existing signal mask
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
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
return value of PTHREAD_ATTR_NO_SIGMASK_NP indicates
that the signal mask attribute is not set in
On error, these functions return a positive error number.
These functions are provided by glibc since version 2.32.
These functions are nonstandard GNU extensions; hence the suffix "_np" (nonportable) in the names.
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
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.
This page is part of release 5.10 of the Linux
project. A description of the project, information about reporting bugs,
and the latest version of this page, can be found at