call used to implement pthread_kill (3).) sigqueue (3) Sends a real-time signal with ... sent using kill (2) or sigqueue (3). A thread-directed signal is one thatsigpause (3) sigpending (2) sigprocmask (2) sigqueue (2) sigset (3) sigsuspend (2) sleep (3) sockatmarksupported. The following functions are present: sigqueue () sigtimedwait () sigwaitinfo () --- - _POSIX_REGEXP - _SC_REGEXP If thissigaction (2), pthread_kill (3), and pthread_sigqueue (3) interfaces fail with the error EINVALpthread_setspecific (3), pthread_sigmask (3), pthread_sigqueue (3), and pthread_testcancelsetpriority (2), setpgid (2), setsid (2), sigqueue (3), and waitpid (2). A process