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.\"
.\" Copyright (C) 1997 Jerry Epplin. All rights reserved.
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one
.\"
.\" The author assumes no responsibility for errors or omissions, or for
.\" damages resulting from the use of the information contained herein.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.TH RTF_CREATE_HANDLER 2 "11 July 1997" "Real-Time Linux" "Real-Time Linux"
.SH NAME
rtf_create_handler \- install a handler for real-time fifo data
.SH SYNOPSIS
.nf
.B #define MODULE
.B #include <linux/module.h>
.B #include <linux/kernel.h>
.B #include <linux/version.h>
.B #include <linux/errno.h>
.B #include <linux/rtf.h>
.fi
.sp
.BI "int rtf_create_handler(unsigned int " fifo ", int (* " handler ")(unsigned int fifo));
.SH DESCRIPTION
.B rtf_create_handler
installs a handler which is executed when data is written to or read from a real-time
fifo (RT-FIFO).
.I fifo
is an RT-FIFO that must have previously been created with a call to
.BR rtf_create_fifo .
.I handler
is then called whenever a Linux process accesses that fifo.
.PP
.B rtf_create_handler
is often used in conjunction with
.B rtf_get
to process data acquired asynchronously from a Linux process. The installed handler
calls
.B rtf_get
when data is present. Because the handler is only executed when there is activity
on the fifo, polling is not necessary.
.PP
The RT-FIFO is a mechanism, implemented as a character device, to
communicate between real-time tasks and ordinary Linux processes. The
rtf_* functions are used by the real-time tasks; Linux processes use
standard character device access functions such as
.BR read(2) ,
.BR write(2) ,
and
.BR select(2) .
.SH "RETURN VALUE"
On success, 0 is returned. On failure, a negative value is returned as described below.
.SH ERRORS
.IP \fB-EINVAL\fP
.I fifo
is greater than or equal to RTF_NO, or is not a valid RT-FIFO identifier; or
.I handler
is NULL.
.SH "SEE ALSO"
.BR rtf_create (2),
.BR rtf_destroy (2),
.BR rtf_get (2),
.BR rtf_put (2),
.BR rtf_resize (2)
.SH AUTHOR
This manual page was written by Jerry Epplin.
.P
Copyright (C) 1997 Jerry Epplin, placed under the GNU General Public
License, see the file copyright for details.
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