When applying signals for process communication, it might be more appropriate for a process to suspend itself until the occurrence of a specific signal, and resume execution on the arrival of a signal from another process. The POSIX calls sigsuspend(), sigwaitinfo(), and sigtimedwait() provide this functionality:

int sigsuspend(const sigset_t *mask);
int sigwaitinfo(const sigset_t *set, siginfo_t *info);
int sigtimedwait(const sigset_t *set, siginfo_t *info, const struct timespec *timeout);

While all of these APIs allow a process to wait for a specified signal to occur, sigwaitinfo() provides additional data about the signal through the siginfo_t instance returned through the info pointer. sigtimedwait() extends the functionality by providing an additional argument that allows the operation to time out, making it a bounded wait call. The Linux kernel provides an alternate API that allows the process to be notified about the occurrence of a signal through a special file descriptor called signalfd():

 #include <sys/signalfd.h>
 int signalfd(int fd, const sigset_t *mask, int flags);

On success, signalfd() returns a file descriptor, on which the process needs to invoke read(), which blocks until any of the signals specified in the mask occur.