gistfile1.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

int main(void)
{
    fd_set bar;
    struct timeval foo;
    int ret;

   /* Watch stdin (fd 0) to see when it has input.  As per unix man example*/
    FD_ZERO(&bar);
    FD_SET(0, &bar);

    foo.tv_sec = 5;
    foo.tv_usec = 0;
   ret = select(1, &bar, NULL, NULL, &foo);


   if (ret == -1)
   {
        perror("select()");
   }
    else if (ret)
   {
        printf("Data is available now.\n");
        /* rfds is true*/
   }
    else
   {
        printf("No data within five seconds.\n");
	}
	return 0;
}