poll()

Returns: count of ready descriptors, 0 on timeout, −1 on error

Example

#include <stdio.h>
#include <poll.h>
 
int main(void)
{
	struct pollfd pfds[1]; // More if you want to monitor more
 
	pfds[0].fd = 0;          // Standard input
	pfds[0].events = POLLIN; // Tell me when ready to read
 
	// If you needed to monitor other things, as well:
	//pfds[1].fd = some_socket; // Some socket descriptor
	//pfds[1].events = POLLIN;  // Tell me when ready to read
 
	printf("Hit RETURN or wait 2.5 seconds for timeout\n");
 
	int num_events = poll(pfds, 1, 2500); // 2.5 second timeout
 
	if (num_events == 0) {
		printf("Poll timed out!\n");
	} else {
		int pollin_happened = pfds[0].revents & POLLIN;
 
		if (pollin_happened) {
			printf("File descriptor %d is ready to read\n", pfds[0].fd);
		} else {
			printf("Unexpected event occurred: %d\n", pfds[0].revents);
		}
	}
 
	return 0;
}