使用select()达到输入延时的效果

#include <stdio.h>#include <stdlib.h>#include <string.h>#define STDIN 0 /* file descriptor for standard input */int main(int argc, char *argv[]){struct timeval tv; fd_set readfds; tv.tv_sec = 2; tv.tv_usec = 500000; FD_ZERO(&readfds); FD_SET(STDIN, &readfds); /* don't care about writefds and exceptfds: */ select(STDIN+1, &readfds, NULL, NULL, &tv); if (FD_ISSET(STDIN, &readfds))printf("A key was pressed!\n"); else printf("Timed out.\n");return 0;}