ndelay_on - Man Page

#include <ndelay.h>

extern int ndelay_on(int fd);

ndelay_on puts a file descriptor in non-blocking mode.  Reading from and writing to non-blocking network sockets, FIFOs or device files will return immediately, even if not as many bytes have been processed as were specified.

If an error occurred, ndelay_on will return nonzero and set errno accordingly.

fcntl(2), ndelay_off(3)

ndelay_off(3).