Multi-task I/O select function

# Include <stdio. h>
# Include <sys/time. h>
# Include <sys/types. h>
# Include <unistd. h>

Int main (void ){
Struct timeval TV;
Fd_set readfds;
Int ret;

// Wait for stdin Input
Fd_zero (& readfds); // remove all
Fd_set (stdin_fileno, & readfds); // Add to group
// Fd_clr is used to remove

// Set the wait time
TV. TV _sec = 5;
TV. TV _usec = 0;

// The first parameter is the maximum number of the file descriptor plus 1
Ret = select (stdin_fileno + 1, & readfds, null, null, & TV );

If (ret =-1 ){
Perror ("select ");
Return 1;
} Else if (! RET ){
Printf ("time out \ n ");
Return 0;
}
// Check whether stdin_fileno can be read without being blocked.
If (fd_isset (stdin_fileno, & readfds )){
Char Buf [1025];
Int Len;
// It will not block
Len = read (stdin_fileno, Buf, 1024 );
If (LEN =-1 ){
Perror ("read ");
Return 1;
}
If (LEN ){
Buf [Len] = '\ 0 ';
Printf ("read: % s \ n", Buf );
}
Return 0;
}
Printf ("won't happen \ n ");
Return 1;
}