67 lines
1.4 KiB
C
67 lines
1.4 KiB
C
|
/*++
|
||
|
/* NAME
|
||
|
/* non_blocking 3
|
||
|
/* SUMMARY
|
||
|
/* set/clear non-blocking flag
|
||
|
/* SYNOPSIS
|
||
|
/* #include <iostuff.h>
|
||
|
/*
|
||
|
/* int non_blocking(int fd, int on)
|
||
|
/* DESCRIPTION
|
||
|
/* the \fInon_blocking\fR() function manipulates the non-blocking
|
||
|
/* flag for the specified open file, and returns the old setting.
|
||
|
/*
|
||
|
/* Arguments:
|
||
|
/* .IP fd
|
||
|
/* A file descriptor.
|
||
|
/* .IP on
|
||
|
/* For non-blocking I/O, specify a non-zero value (or use the
|
||
|
/* NON_BLOCKING constant); for blocking I/O, specify zero
|
||
|
/* (or use the BLOCKING constant).
|
||
|
/*
|
||
|
/* The result is non-zero when the non-blocking flag was enabled.
|
||
|
/* DIAGNOSTICS
|
||
|
/* All errors are fatal.
|
||
|
/* LICENSE
|
||
|
/* .ad
|
||
|
/* .fi
|
||
|
/* The Secure Mailer license must be distributed with this software.
|
||
|
/* AUTHOR(S)
|
||
|
/* Wietse Venema
|
||
|
/* IBM T.J. Watson Research
|
||
|
/* P.O. Box 704
|
||
|
/* Yorktown Heights, NY 10598, USA
|
||
|
/*--*/
|
||
|
|
||
|
/* System interfaces. */
|
||
|
|
||
|
#include "sys_defs.h"
|
||
|
#include <fcntl.h>
|
||
|
|
||
|
/* Utility library. */
|
||
|
|
||
|
#include "msg.h"
|
||
|
#include "iostuff.h"
|
||
|
|
||
|
/* Backwards compatibility */
|
||
|
#ifdef FNDELAY
|
||
|
#define PATTERN FNDELAY
|
||
|
#else
|
||
|
#define PATTERN O_NONBLOCK
|
||
|
#endif
|
||
|
|
||
|
/* non_blocking - set/clear non-blocking flag */
|
||
|
|
||
|
int non_blocking(fd, on)
|
||
|
int fd;
|
||
|
int on;
|
||
|
{
|
||
|
int flags;
|
||
|
|
||
|
if ((flags = fcntl(fd, F_GETFL, 0)) < 0)
|
||
|
msg_fatal("fcntl: get flags: %m");
|
||
|
if (fcntl(fd, F_SETFL, on ? flags | PATTERN : flags & ~PATTERN) < 0)
|
||
|
msg_fatal("fcntl: set non-blocking flag %s: %m", on ? "on" : "off");
|
||
|
return ((flags & PATTERN) != 0);
|
||
|
}
|