FD_CLR(3) Library Functions Manual FD_CLR(3)

FD_CLR — macros for synchronous I/O multiplexing

#include <sys/time.h>

FD_CLR(int fd, fd_set *fdset);
FD_ISSET(int fd, fd_set *fdset);
FD_SET(int fd, fd_set *fdset);
FD_ZERO(fd_set *fdset);

Refer to select(3) .

<sys/time.h> .

February 1997 posix.fail