pthread_attr_setsigmask_np, pthread_attr_getsigmask_np - set/get signal mask
attribute in thread attributes object
POSIX threads library (
libpthread,
-lpthread)
#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);
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.
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.
- ENOMEM
- (pthread_attr_setsigmask_np()) Could not allocate
memory.
These functions are provided since glibc 2.32.
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 |
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 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.
sigprocmask(2),
pthread_attr_init(3),
pthread_sigmask(3),
pthreads(7),
signal(7)