The pause is a very good example of a blocking call; when a process calls this API, it blocks, that is, it goes to sleep waiting for an event; the event: the arrival of any signal to it. The moment a signal arrives, the pause is unblocked and execution continues. Of course, delivery of a fatal signal will cause the unsuspecting process to die:

include <unistd.h>
 int pause(void);

Throughout, we have said that checking system calls for their failure case -1 is considered very important: a best practice to always follow. The pause(2) throws up an interesting exception case: it seems to be the one system call that always returns -1 and errno is set to the value EINTR Interrupted system call (the interruption being the signal of course).

For this reason, we often code the pause as follows:

(void)pause();

The typecast to void is to inform tools such as the compiler and static analyzers that we don't really care about the return value from pause.