pthread_sigqueue - queue a signal and data to a thread

       For an explanation of the terms used in this section, see attributes(7).
       ┌─────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                                                                   │ Attribute     │ Value   │
       ├─────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │ pthread_sigqueue()                                                          │ Thread safety │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

       The pthread_sigqueue() function performs a similar task to sigqueue(3), but, rather than sending a signal
       to a process, it sends a signal to a thread in the same process as the calling thread.

       The  thread argument is the ID of a thread in the same process as the caller.  The sig argument specifies
       the signal to be sent.  The value argument specifies data to accompany the signal;  see  sigqueue(3)  for
       details.

EAGAIN The  limit  of  signals  which  may  be  queued  has  been  reached.   (See  signal(7) for further
              information.)

       EINVALsig was invalid.

       ENOSYSpthread_sigqueue() is not supported on this system.

       ESRCHthread is not valid.

       glibc 2.11.

       POSIX threads library (libpthread, -lpthread)

       pthread_sigqueue - queue a signal and data to a thread

       On success, pthread_sigqueue() returns 0; on error, it returns an error number.

rt_tgsigqueueinfo(2), sigaction(2), pthread_sigmask(3), sigqueue(3), sigwait(3), pthreads(7), signal(7)

Linux man-pages 6.9.1                              2024-05-02                                pthread_sigqueue(3)

       GNU.

#include<signal.h>#include<pthread.h>intpthread_sigqueue(pthread_tthread,intsig,constunionsigvalvalue);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       pthread_sigqueue():
           _GNU_SOURCE

       The glibc implementation of pthread_sigqueue() gives an error (EINVAL) on attempts to send either of  the
       real-time signals used internally by the NPTL threading implementation.  See nptl(7) for details.