Edouard@734: <?xml version="1.0" encoding="UTF-8" standalone="no"?>
Edouard@734: <CFile xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.w3.org/2001/XMLSchema" xsi:schemaLocation="cext_xsd.xsd">
Edouard@734:   <includes>
Edouard@953: <![CDATA[#include "stdio.h"]]>
Edouard@734:   </includes>
Edouard@859:   <variables>
Edouard@859:     <variable name="TestInput" type="SINT" class="input"/>
Edouard@860:     <variable name="TestOutput" type="SINT" class="output"/>
Edouard@859:   </variables>
Edouard@734:   <globals>
Edouard@859: <![CDATA[volatile long Lock=0;
Edouard@859: volatile char PtoC=1,CtoP=2;
Edouard@859: 
Edouard@859: int Simple_C_Call(int val){
Edouard@859:   return val+1;
Edouard@734: }
Edouard@859: 
Edouard@862: int Python_to_C_Call(char toC, char *fromC){
Edouard@859:   /* Code called by python should never touch to 
Edouard@859:      variables modified by PLC thread directly
Edouard@859: 
Edouard@859:      AtomicCompareExchange comes from 
Edouard@859:      beremiz' runtime implementation */
Edouard@859: 
Edouard@859:   int res = 0;
Edouard@859:   if(!AtomicCompareExchange(&Lock, 0, 1)){
Edouard@859:     PtoC=toC;
Edouard@859:     *fromC=CtoP;
Edouard@859:     AtomicCompareExchange(&Lock, 1, 0);
Edouard@859:     res=1;
Edouard@859:   }
Edouard@859:   printf("C code called by Python: toC %d fromC %d\n",toC,*fromC);
Edouard@859:   return res;
Edouard@859: }
Edouard@859: 
Edouard@862: int PLC_C_Call(char fromPLC, char *toPLC){
Edouard@859:   /* PLC also have to be realy carefull not to 
Edouard@859:      conflict with asynchronous python access */
Edouard@859:   int res;
Edouard@859:   if(!AtomicCompareExchange(&Lock, 0, 1)){
Edouard@859:       CtoP = fromPLC;
Edouard@859:       *toPLC = PtoC;
Edouard@859:       AtomicCompareExchange(&Lock, 1, 0);
Edouard@859:       return 1;
Edouard@859:   }
Edouard@859:   return 0;
Edouard@859: }]]>
Edouard@734:   </globals>
Edouard@734:   <initFunction>
Edouard@734: <![CDATA[]]>
Edouard@734:   </initFunction>
Edouard@734:   <cleanUpFunction>
Edouard@734: <![CDATA[]]>
Edouard@734:   </cleanUpFunction>
Edouard@734:   <retrieveFunction>
Edouard@734: <![CDATA[]]>
Edouard@734:   </retrieveFunction>
Edouard@734:   <publishFunction>
Edouard@860: <![CDATA[if(!AtomicCompareExchange(&Lock, 0, 1)){
Edouard@860:     TestInput = CtoP + PtoC + TestOutput;
Edouard@860:     AtomicCompareExchange(&Lock, 1, 0);
Edouard@860: }]]>
Edouard@734:   </publishFunction>
Edouard@734: </CFile>