source: trunk/minix/test/select/test09.c@ 16

/*
 * Test name: test09.c
 *
 * Objetive: The purpose of this test is to make sure that select works
 * when working with the terminal.
 *
 * Description:  This tests wait entry from stdin using select and displays
 * it again in stdout when it is ready to write (which is always)
 * 
 * Jose M. Gomez
 */

#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/select.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

void main(void) {
        fd_set fds_read, fds_write;
        int retval;
        char data[1024];

        FD_ZERO(&fds_read);
        FD_ZERO(&fds_write);
        FD_SET(0, &fds_read);           /* stdin */
        FD_SET(1, &fds_write);          /* stdout */

        while(1) {
                printf("Input some data: ");
                fflush(stdout);
                retval=select(3, &fds_read, NULL, NULL, NULL); 
                if (retval < 0) {
                        fprintf(stderr, "Error while executing select\n");
                        exit(-1);
                }
                printf("select retval: %d\n", retval);
                if (!FD_ISSET(0, &fds_read)) {
                        fprintf(stderr, "Error: stdin not ready (?)\n");
                        exit(-1);
                }
                printf("gets..\n");
                gets(data);
                printf("gets done..\n");
                if (!strcmp(data, "exit"))
                        exit(0);
                printf("Try to write it back\n");
                retval=select(3, NULL, &fds_write, NULL, NULL);
                if (retval < 0) {
                        fprintf(stderr, "Error while executing select\n");
                        exit(-1);
                }
                if (!FD_ISSET(1, &fds_write)) {
                        fprintf(stderr, "Error: stdout not ready (?)\n");
                        exit(-1);
                }
                printf("Data: %s\n", data);
        }
}