Setting a file descriptor to blocking or non-blocking mode (C recipe) by Emilio Monti

ActiveState Code (http://code.activestate.com/recipes/577384/)

#include <fcntl.h>

/** 
 * Set a file descriptor to blocking or non-blocking mode.
 *
 * @param fd The file descriptor
 * @param blocking 0:non-blocking mode, 1:blocking mode
 *
 * @return 1:success, 0:failure.
 **/
int fd_set_blocking(int fd, int blocking) {
    /* Save the current flags */
    int flags = fcntl(fd, F_GETFL, 0);
    if (flags == -1)
        return 0;

    if (blocking)
        flags &= ~O_NONBLOCK;
    else
        flags |= O_NONBLOCK;
    return fcntl(fd, F_SETFL, flags) != -1;
}