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.\" This -*- nroff -*- file has been generated from
.\" DocBook SGML with docbook-to-man on Debian GNU/Linux.
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.TH "rtf_create_handler" "3"
.SH "NAME"
rtf_create_handler \(em install a handler for realtime fifo data
.SH "SYNOPSIS"
.PP
.nf
.ta 8n 16n 24n 32n 40n 48n 56n 64n 72n
#include <rtl_fifo.h>
int \fBrtf_create_handler\fP(unsigned int \fBfifo\fR, int (* \fBhandler\fR)());
.fi
.SH "DESCRIPTION"
.PP
\fBrtf_create_handler\fP installs a handler which is executed when data is written to or read from a real-time fifo (RT-FIFO) by a user-space process. \fBfifo\fR is an RT-FIFO that must have previously been created with a call to \fBrtf_create\fP. \fBhandler\fR is then called whenever a Linux process accesses that fifo. The handler is executed with the Linux (i.e., lowest) priority.
.PP
\fBrtf_create_handler\fP is often used in conjunction with rtf_get to process data acquired asynchronously from a Linux process. The installed handler calls \fBrtf_get\fP 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 realtime software components (either in threads or handlers),
and between realtime software and ordinary Linux processes. The rtf_* functions are used in RT mode; Linux processes use standard character device access functions such as \fBread(2)\fP, \fBwrite(2)\fP and \fBselect(2)\fP.
.SH "RETURN VALUE"
.PP
On success, 0 is returned. On failure, a negative value is returned as described below.
.SH "NOTES"
.PP
The handler is only called when a Linux process accesses the FIFO. To install a handler that would be called on \fBrtf_put\fP or \fBrtf_get\fP, use \fBrtf_create_rt_handler\fP.
.SH "ERRORS"
.IP "-EINVAL" 10
\fBfifo\fR is greater than or equal to RTF_NO, or is not a valid RT-FIFO identifier; or \fBhandler\fR is NULL.
.SH "SEE ALSO"
\fIrtf_create(3) (link to URL rtf_create.3.html) \fR, \fIrtf_create_rt_handler(3) (link to URL rtf_create_rt_handler.3.html) \fR, \fIrtf_destroy(3) (link to URL rtf_destroy.3.html) \fR, \fIrtf_get(3) (link to URL rtf_get.3.html) \fR, \fIrtf_put(3) (link to URL rtf_put.3.html) \fR
.PP
\(co1997 Jerry Epplin.
.PP
Modifications for RTLinux 2.x and 3.x by Michael Barabanov. \(co2001 FSMLabs Inc.
.PP
All rights reserved.
...\" created by instant / docbook-to-man, Wed 13 Jun 2001, 17:58
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