int main(int argc, char *argv[])
{
int fd1, fd2, fd3, fd4, fd5, fd6; /* file descriptors of files */
fd_set fds_read, fds_write;
int retval;
/* Creates the dummy files with different modes */
fd1 = open("dummy1.txt", O_CREAT | O_RDONLY);
if (fd1 < 0) {
perror("Error opening file");
exit(-1);
}
fd2 = open("dummy2.txt", O_CREAT | O_RDONLY);
if (fd2 < 0) {
perror("Error opening file");
exit(-1);
}
fd3 = open("dummy3.txt", O_CREAT | O_WRONLY);
if (fd3 < 0) {
perror("Error opening file");
exit(-1);
}
fd4 = open("dummy4.txt", O_CREAT | O_WRONLY);
if (fd4 < 0) {
perror("Error opening file");
exit(-1);
}
fd5 = open("dummy5.txt", O_CREAT | O_RDWR);
if (fd5 < 0) {
perror("Error opening file");
exit(-1);
}
fd6 = open("dummy6.txt", O_CREAT | O_RDWR);
if (fd6 < 0) {
perror("Error opening file");
exit(-1);
}
/* Create the fd_set structures */
FD_ZERO(&fds_read);
FD_ZERO(&fds_write);
FD_SET(fd1, &fds_read); /* fd1 => O_RDONLY */
FD_SET(fd2, &fds_read); /* fd2 => O_RDONLY */
FD_SET(fd3, &fds_write); /* fd3 => O_WRONLY */
FD_SET(fd4, &fds_write); /* fd4 => O_WRONLY */
FD_SET(fd5, &fds_read); /* fd5 => O_RDWR */
FD_SET(fd5, &fds_write); /* fd5 => O_RDWR */
FD_SET(fd6, &fds_read); /* fd6 => O_RDWR */
FD_SET(fd6, &fds_write); /* fd6 => O_RDWR */
printf("* Dump INPUT fds_read:\n");
dump_fdset(&fds_read);
printf("* Dump INPUT fds_write:\n");
dump_fdset(&fds_write);
retval=select(9, &fds_read, &fds_write, NULL, NULL);
printf("\n***********************\n");
printf("After select: \n");
printf("Return value: %d\n", retval);
printf("* Dump RESULTING fds_read:\n");
dump_fdset(&fds_read);
printf("* Dump RESULTING fds_write:\n");
dump_fdset(&fds_write);
/* close and delete dummy files */
close(fd1);
close(fd2);
close(fd3);
close(fd4);
close(fd5);
close(fd6);
unlink("dummy1.txt");
unlink("dummy2.txt");
unlink("dummy3.txt");
unlink("dummy4.txt");
unlink("dummy5.txt");
unlink("dummy6.txt");
return 0;
}
void main(void) {
int fd1, fd2, fd3, fd4, fd5, fd6; /* file descriptors of files */
fd_set fds_read, fds_write; /* bit maps */
struct timeval timeout; /* timeout */
int retval; /* ret value */
/* Creates the dummy files with different modes */
fd1 = open("dummy1.txt", O_CREAT | O_RDONLY);
if (fd1 < 0) {
perror("Error opening file");
exit(-1);
}
fd2 = open("dummy2.txt", O_CREAT | O_RDONLY);
if (fd2 < 0) {
perror("Error opening file");
exit(-1);
}
fd3 = open("dummy3.txt", O_CREAT | O_WRONLY);
if (fd3 < 0) {
perror("Error opening file");
exit(-1);
}
fd4 = open("dummy4.txt", O_CREAT | O_WRONLY);
if (fd4 < 0) {
perror("Error opening file");
exit(-1);
}
fd5 = open("dummy5.txt", O_CREAT | O_RDWR);
if (fd5 < 0) {
perror("Error opening file");
exit(-1);
}
fd6 = open("dummy6.txt", O_CREAT | O_RDWR);
if (fd6 < 0) {
perror("Error opening file");
exit(-1);
}
/* Create the fd_set structures */
FD_ZERO(&fds_read);
FD_ZERO(&fds_write);
FD_SET(fd1, &fds_write); /* fd1 => O_RDONLY */
FD_SET(fd2, &fds_write); /* fd2 => O_RDONLY */
FD_SET(fd3, &fds_read); /* fd3 => O_WRONLY */
FD_SET(fd4, &fds_read); /* fd4 => O_WRONLY */
FD_SET(fd5, &fds_read); /* fd5 => O_RDWR */
FD_SET(fd5, &fds_write); /* fd5 => O_RDWR */
FD_SET(fd6, &fds_read); /* fd6 => O_RDWR */
FD_SET(fd6, &fds_write); /* fd6 => O_RDWR */
printf("* Dump INPUT fds_read:\n");
dump_fdset(&fds_read);
printf("* Dump INPUT fds_write:\n");
dump_fdset(&fds_write);
retval=select(9, &fds_read, &fds_write, NULL, NULL);
printf("\n***********************\n");
printf("After select: \n");
printf("Return value: %d\n", retval);
printf("* Dump RESULTING fds_read:\n");
dump_fdset(&fds_read);
printf("* Dump RESULTING fds_write:\n");
dump_fdset(&fds_write);
/* make a select call where none of them are ready (don't use fd5 and fd6) */
FD_ZERO(&fds_read);
FD_ZERO(&fds_write);
FD_SET(fd1, &fds_write); /* fd1 => O_RDONLY */
FD_SET(fd2, &fds_write); /* fd2 => O_RDONLY */
FD_SET(fd3, &fds_read); /* fd3 => O_WRONLY */
FD_SET(fd4, &fds_read); /* fd4 => O_WRONLY */
/* make a select call where none of them are ready (don't use fd5 and fd6) */
/* create a timeout as well */
timeout.tv_sec = 5;
timeout.tv_usec = 0;
retval=select(7, &fds_read, &fds_write, NULL, NULL);
printf("\n***********************\n");
printf("After select: \n");
printf("Return value: %d\n", retval);
printf("* Dump RESULTING fds_read:\n");
dump_fdset(&fds_read);
printf("* Dump RESULTING fds_write:\n");
dump_fdset(&fds_write);
/* close and delete dummy files */
close(fd1);
close(fd2);
close(fd3);
close(fd4);
close(fd5);
close(fd6);
unlink("dummy1.txt");
unlink("dummy2.txt");
unlink("dummy3.txt");
unlink("dummy4.txt");
unlink("dummy5.txt");
unlink("dummy6.txt");
}
