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<HTML><HEAD>   <TITLE>RTAI 1.0 documentation - RPC</TITLE>   <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">   <META NAME="Generator" CONTENT="VIM - Vi IMproved 5.3"></HEAD><BODY><A NAME="rt_rpc"></A><dl><dt><H3>NAME</H3></dt><dd>rt_rpc - make a remote procedure call</dd></dl><dl><dt><H3>SYNOPSIS</H3></dt><dd>#include "rtai_sched.h"<p><B>RT_TASK *rt_rpc (RT_TASK *</B><I>task</I><B>,	unsigned int </B><I>msg</I><B>,	unsigned int *</B><I>reply</I><B>);</B></dd></dl><dl><dt><H3>DESCRIPTION</H3></dt><dd><b>rt_rpc</b> makes a Remote Procedure Call.RPC is like a send/receive pair.<b>rt_rpc</b> sends the message <I>msg</I>to the task <I>task</I> then waits until a reply is received.The caller task is always blocked and queued up.(Queueing may happen in priority order or on FIFO base.This is determined by compile time option MSG_PRIORD.)<br>The receiver task may get the message with any <b>rt_receive_*</b> function.It can send the answer with <b>rt_return</b>.<br><i>reply</i> points to a buffer provided by the caller.</dd></dl><dl><dt><H3>RETURN VALUE</H3></dt><dd>On success, <i>task</i> (the pointer to the task that received the message)is returned.If message has not been sent (e.g. thetask <I>task</I> was killed before receiving the message) 0 is returned.On other failure, a special value is returned as described below.</dd></dl><dl><dt><H3>ERRORS</H3></dt><dd>        <dl><dt>        <code>0</code>        </dt><dd>        The receiver task was killed before receiving the message.        </dd></dl>        <dl><dt>        <code>0xffff</code>        </dt><dd>        <I>task</I> does not refer to a valid task.        </dd></dl></dd></dl><dl><dt><H3>BUGS</H3></dt><dd>There is no guarantee, that the value of pointer <i>task</i> differs from<code>0xffff</code>. In this theoretical case the caller cannot figureout if the operation was succesful or not.</dd></dl><dl><dt><H3>SEE ALSO</H3></dt><dd><a href="message.html#rt_receive">rt_receive_*</a>,<a href="#rt_return">rt_return</a>,<a href="#rt_isrpc">rt_isrpc</a>.</dd></dl><p align=right><A HREF="manual.html#rpc">[return to index]</A></p><HR ALIGN=LEFT SIZE=1 NOSHADE WIDTH="100%"><!-- -------------------------------------------------------- --><A NAME="rt_rpc_if"></A><dl><dt><H3>NAME</H3></dt><dd>rt_rpc_if - make a remote procedure call if receiver is ready</dd></dl><dl><dt><H3>SYNOPSIS</H3></dt><dd>#include "rtai_sched.h"<p><B>RT_TASK *rt_rpc_if (RT_TASK *</B><I>task</I><B>,	unsigned int </B><I>msg</I><B>,	unsigned int *</B><I>reply</I><B>);</B></dd></dl><dl><dt><H3>DESCRIPTION</H3></dt><dd><b>rt_rpc_if</b> tries to make a Remote Procedure Call.If the receiver task is ready to accept a message <b>rt_rpc_if</b>sends the message <I>msg</I> then waits until a reply is received.In this case the caller task is blocked and queued up.(Queueing may happen in priority order or on FIFO base.This is determined by compile time option MSG_PRIORD.)If the receiver is not ready <b>rt_rpc_if</b> returns immediately.<br>The receiver task may get the message with any <b>rt_receive_*</b> function.It can send the answer with <b>rt_return</b>.<br><i>reply</i> points to a buffer provided by the caller.</dd></dl><dl><dt><H3>RETURN VALUE</H3></dt><dd>On success, <i>task</i> (the pointer to the task that received the message)is returned.If message has not been sent, 0 is returned.On other failure, a special value is returned as described below.</dd></dl><dl><dt><H3>ERRORS</H3></dt><dd>	<dl><dt>	<code>0</code>	</dt><dd>	The task <i>task</i> was not ready to receive the message or	it was killed before sending the reply.	</dd></dl>	<dl><dt>	<code>0xffff</code>	</dt><dd>	<I>task</I> does not refer to a valid task.	</dd></dl></dd></dl><dl><dt><H3>BUGS</H3></dt><dd>There is no guarantee, that the value of pointer <i>task</i> differs from<code>0xffff</code>. In this theoretical case the caller cannot figureout if the operation was succesful or not.</dd></dl><dl><dt><H3>SEE ALSO</H3></dt><dd><a href="message.html#rt_receive">rt_receive_*</a>,<a href="#rt_return">rt_return</a>,<a href="#rt_isrpc">rt_isrpc</a>.</dd></dl><p align=right><A HREF="manual.html#rpc">[return to index]</A></p><HR ALIGN=LEFT SIZE=1 NOSHADE WIDTH="100%"><!-- -------------------------------------------------------- --><A NAME="rt_rpc_until"></A><A NAME="rt_rpc_timed"></A><dl><dt><H3>NAME</H3></dt><dd>rt_rpc_until, rt_rpc_timed - make a remote procedure call with timeout</dd></dl><dl><dt><H3>SYNOPSIS</H3></dt><dd>#include "rtai_sched.h"<p><B>RT_TASK *rt_rpc_until (RT_TASK *</B><I>task</I><B>,	unsigned int </B><I>msg</I><B>,	unsigned int *</B><I>reply</I><B>,	RTIME </b><i>time</i><b>);</B><p><B>RT_TASK *rt_rpc_timed (RT_TASK *</B><I>task</I><B>,	unsigned int </B><I>msg</I><B>,	unsigned int *</B><I>reply</I><B>,	RTIME </b><i>delay</i><b>);</B></dd></dl><dl><dt><H3>DESCRIPTION</H3></dt><dd><b>rt_rpc_until</b> and <b>rt_rpc_timed</b> make a Remote Procedure Call.They send the message <I>msg</I> to the task <I>task</I> then waituntil a reply is received or a timeout occurs.The caller task is always blocked and queued up.(Queueing may happen in priority order or on FIFO base.This is determined by compile time option MSG_PRIORD.)<br>The receiver task may get the message with any <b>rt_receive_*</b> function.It can send the answer with <b>rt_return</b>.<br><i>reply</i> points to a buffer provided by the caller.<br><i>time</i> is an absolute value.<i>delay</i> is relative to the current time.</dd></dl><dl><dt><H3>RETURN VALUE</H3></dt><dd>On success, <i>task</i> (the pointer to the task that received the message)is returned.If message has not been sent or no answer arrived, 0 is returned.On other failure, a special value is returned as described below.</dd></dl><dl><dt><H3>ERRORS</H3></dt><dd>        <dl><dt>        <code>0</code>        </dt><dd>        The message could not be sent or the answer did not arrived in time.        </dd></dl>        <dl><dt>        <code>0xffff</code>        </dt><dd>        <I>task</I> does not refer to a valid task.        </dd></dl></dd></dl><dl><dt><H3>BUGS</H3></dt><dd>There is no guarantee, that the value of pointer <i>task</i> differs from<code>0xffff</code>. In this theoretical case the caller cannot figureout if the operation was succesful or not.</dd></dl><dl><dt><H3>SEE ALSO</H3></dt><dd><a href="message.html#rt_receive">rt_receive_*</a>,<a href="#rt_return">rt_return</a>,<a href="#rt_isrpc">rt_isrpc</a>.</dd></dl><p align=right><A HREF="manual.html#rpc">[return to index]</A></p><HR ALIGN=LEFT SIZE=1 NOSHADE WIDTH="100%"><!-- -------------------------------------------------------- --><A NAME="rt_isrpc"></A><dl><dt><H3>NAME</H3></dt><dd>rt_isrpc - check if sender waits for reply or not</dd></dl><dl><dt><H3>SYNOPSIS</H3></dt><dd>#include "rtai_sched.h"<p><b>int rt_isrpc (RT_TASK *</B><I>task</I><B>);</b></dd></dl><dl><dt><H3>DESCRIPTION</H3></dt><dd>After receiving a message, by calling <b>rt_isrpc</b> a task can figure outwhether the sender task <i>task</i> is waiting for a reply or not.<br>No answer is required if the message sent by a <b>rt_send_*</b>function or the sender called <b>rt_rpc_timed</b> or <b>rt_rpc_until</b>but it is already timed out.</dd></dl><dl><dt><H3>RETURN VALUE</H3></dt><dd>If the <i>task</i> waits for a reply, a nonzero value is returned.Otherwise 0 is returned.</dd></dl><dl><dt><H3>BUGS</H3></dt><dd><b>rt_isrpc</b> does not perform any check on pointer <i>task</i>.<br><b>rt_isrpc</b> cannot figure out what RPC result the sender is waiting for.</dd></dl><dl><dt><H3>COMMENTS</H3></dt><dd><b>rt_return</b> is intelligent enough to not send an answer toa task which is not waiting for it. Therefore using <b>rt_isrpc</b> is notnecessary and discouraged.</dd></dl><p align=right><A HREF="manual.html#rpc">[return to index]</A></p><HR ALIGN=LEFT SIZE=1 NOSHADE WIDTH="100%"><!-- -------------------------------------------------------- --><dl><dt><H3>NAME</H3></dt><dd>rt_return - send back the result of a remote procedure call</dd></dl><dl><dt><H3>SYNOPSIS</H3></dt><dd>#include "rtai_sched.h"<p><B>RT_TASK *rt_return (RT_TASK *</B><I>task</I><B>,	unsigned int </B><I>result</I><B>);</B></dd></dl><dl><dt><H3>DESCRIPTION</H3></dt><dd><b>rt_result</b> sends the result <I>result</I> to the task <I>task</I>.If the task calling <b>rt_rpc*</b> previously is not waitingthe answer (i.e. killed or timed out) this return message is silentlydiscarded.</dd></dl><dl><dt><H3>RETURN VALUE</H3></dt><dd>On success, <i>task</i> (the pointer to the task that is got the the reply)is returned.If the reply message has not been sent, 0 is returned.On other failure, a special value is returned as described below.</dd></dl><dl><dt><H3>ERRORS</H3></dt><dd>	<dl><dt>	<code>0</code>	</dt><dd>	The reply message was not delivered.	</dd></dl>	<dl><dt>	<code>0xffff</code>	</dt><dd>	<I>task</I> does not refer to a valid task.	</dd></dl></dd></dl><dl><dt><H3>BUGS</H3></dt><dd>There is no guarantee, that the value of pointer <i>task</i> differs from<code>0xffff</code>. In this theoretical case the caller cannot figureout if the operation was succesful or not.</dd></dl><p align=right><A HREF="manual.html#rpc">[return to index]</A></p></BODY></HTML>
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