minix/test/select/test09.c

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/*
* 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);
}
}