SELECT 2 "Jun 9, 2005"
C 4 NAME
select, FD_CLR, FD_ISSET, FD_SET, FD_ZERO - synchronous I/O multiplexing
SYNOPSIS
#include <sys/select.h> int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *timeout) void FD_CLR(int fd, fd_set *fdset) int FD_ISSET(int fd, fd_set *fdset) void FD_SET(int fd, fd_set *fdset) void FD_ZERO(fd_set *fdset)
DESCRIPTION
Select examines the file descriptors given in the sets
readfds , writefds , and
errorfds , up to and including file descriptor
nfds -1 , for reading, writing, or exceptional conditions, respectively.
Select currently supports regular files, pipes, named pipes,
sockets, and character devices.
If the
readfds argument is not a null pointer, it points to an object of type fd_set
that on input specifies the file descriptors to be checked for being
ready to read, and on output indicates which file descriptors are ready
to read.
Writefds and
errorfds have an analogous meaning for file descriptors to be checked for being
ready to read, respectively have pending exceptional (error) conditions.