rtf_make_user_pair.3

rtlinux-3.1源代码

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.TH "rtf_make_user_pair" "3" 
.SH "NAME" 
rtf_make_user_pair \(em make a pair of RT-FIFOs act like a bidirectional FIFO 
.SH "SYNOPSIS" 
.PP 
.nf 
.ta 8n 16n 24n 32n 40n 48n 56n 64n 72n 
#include <rtl_fifo.h> 
 
int \fBrtf_make_user_pair\fP(unsigned int \fBN\fR, unsigned int \fBP\fR);       
.fi 
.SH "DESCRIPTION" 
.PP 
\fBrtf_make_user_pair\fP modifies the behaviour of the RT-FIFO 
\fBN\fR: user-space reads of the 
\fB/dev/rtfN\fR are now routed to RT-FIFO 
\fBP\fR.  User-space writes to 
\fB/dev/rtfN\fR continue communicating with fifo 
\fBN\fR. This essentially makes 
\fB/dev/rtfN\fR bidirectional: data sent with 
\fBrtf_put\fP to FIFO \fBP\fR will be read from 
\fB/dev/rtfN\fR; rtf_get on FIFO \fBN\fR gets 
data written to \fB/dev/rtfN\fR. 
RT-FIFO handlers are affected similarly. 
.PP 
The RT-FIFO is a mechanism, implemented as a character device, to communicate between realtime tasks and ordinary Linux processes.  The rtf_* functions are used by the realtime tasks;  Linux processes use standard character device access functions such as \fBread(2)\fP, \fBwrite(2\fP) and \fBselect(2)\fP. 
.SH "RETURN VALUE" 
.PP 
This function returns 0 on success and a negative error code on error. 
.SH "ERRORS" 
.IP "-ENODEV" 10 
\fBN\fR or \fBP\fR is greater than or equal to RTF_NO. 
.IP "-EINVAL" 10 
\fBN\fR or \fBP\fR is not a valid RT-FIFO identifier. 
.SH "NOTES" 
.PP 
This function is useful when implementing Linux character device drivers on 
top of RT-FIFOs. 
.SH "SEE ALSO" 
\fIread(2) (link to URL ../susv2/xns/read.html) \fR, \fIrtf_create(3) (link to URL rtf_create.3.html) \fR, \fIrtf_create_handler(3) (link to URL rtf_create_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_link_user_ioctl(3) (link to URL rtf_link_user_ioctl.3.html) \fR, \fIwrite(2) (link to URL ../susv2/xns/write.html) \fR 
.PP 
\(co2001 FSMLabs Inc. 
.PP 
All rights reserved. 
...\" created by instant / docbook-to-man, Thu 26 Jul 2001, 11:19