FD_ZERO FD_SET FD_CLR FD_ISSET

/*** FD변수 선언 ***/
fd_set readFdSet;
fd_set writeFdSet;
fd_set exceptFdSet;

/*** FD초기화 ***/
FD_ZERO(&readFdSet);
FD_ZERO(&writeFdSet);
FD_ZERO(&exceptFdSet);

/*** FdSet에 해당 fd 정보 설정 ***/
FD_SET (fd, &readFdSet);
FD_SET (fd, &writeFdSet);
FD_SET (fd, &exceptFdSet);

/*** FdSet에 해당 fd 정보 삭제 ***/
FD_CLR (fd, &readFdSet);
FD_CLR (fd, &writeFdSet);
FD_CLR (fd, &exceptFdSet);

/*** FdSet에 fd 정보가 세팅 여부 확인 ***/
FD_ISSET (fd, &readFdSet);