2005-06-17 15:35:21 +02:00
|
|
|
.TH SELECT 2 "Jun 9, 2005"
|
|
|
|
|
.UC 4
|
|
|
|
|
.SH NAME
|
|
|
|
|
select, FD_CLR, FD_ISSET, FD_SET, FD_ZERO \- synchronous I/O multiplexing
|
|
|
|
|
.SH SYNOPSIS
|
|
|
|
|
.nf
|
|
|
|
|
.ft B
|
|
|
|
|
#include <sys/select.h>
|
|
|
|
|
|
|
|
|
|
int select(int \fInfds\fP, fd_set *\fIreadfds\fP, fd_set *\fIwritefds\fP, fd_set *\fIerrorfds\fP, struct timeval *\fItimeout\fP)
|
|
|
|
|
|
|
|
|
|
void FD_CLR(int \fIfd\fP, fd_set *\fIfdset\fP)
|
|
|
|
|
int FD_ISSET(int \fIfd\fP, fd_set *\fIfdset\fP)
|
|
|
|
|
void FD_SET(int \fIfd\fP, fd_set *\fIfdset\fP)
|
|
|
|
|
void FD_ZERO(fd_set *\fIfdset\fP)
|
|
|
|
|
.ft R
|
|
|
|
|
.fi
|
|
|
|
|
.SH DESCRIPTION
|
|
|
|
|
.B Select
|
|
|
|
|
examines the file descriptors given in the sets
|
|
|
|
|
.IR readfds ,
|
|
|
|
|
.IR writefds ,
|
|
|
|
|
and
|
|
|
|
|
.IR errorfds ,
|
|
|
|
|
up to and including file descriptor
|
|
|
|
|
.IR nfds -1
|
|
|
|
|
, for reading, writing, or exceptional conditions, respectively.
|
|
|
|
|
.B Select
|
|
|
|
|
currently supports regular files, pipes, named pipes,
|
2005-07-01 19:57:51 +02:00
|
|
|
inet, and tty file descriptors. Pty fd's still to be done.
|
2005-06-17 15:35:21 +02:00
|
|
|
|
|
|
|
|
If the
|
|
|
|
|
.I 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.
|
|
|
|
|
.I Writefds
|
|
|
|
|
and
|
|
|
|
|
.I errorfds
|
|
|
|
|
have an analogous meaning for file descriptors to be checked for being
|
|
|
|
|
ready to read, respectively have pending exceptional (error) conditions.
|
|
|
|
|
|
