tests/python/c_code@c_ext/cfile.xml
author Edouard Tisserant
Fri, 12 Jul 2019 11:51:47 +0200 (2019-07-12)
changeset 2622 e10a1095f577
parent 1463 de311ffe3961
permissions -rw-r--r--
Fixed repetitive freezing of IDE when connection drops.
when connection lost error was beeing displayed, the involved wxYield
was calling pending plc status periodic update, itself trying to use connector.
At that time connector is still not destroyed and connection
is attempted again when calling GetPLCStatus.
=> Hack : Ensure connector is destroyed before reporting error.
<?xml version='1.0' encoding='utf-8'?>
<CFile xmlns:xhtml="http://www.w3.org/1999/xhtml">
  <includes>
    <xhtml:p><![CDATA[
]]></xhtml:p>
  </includes>
  <variables>
    <variable name="TestInput" type="SINT" initial="0"/>
    <variable name="TestOutput" type="SINT"/>
  </variables>
  <globals>
    <xhtml:p><![CDATA[
volatile long Lock=0;
volatile char PtoC=1,CtoP=2;

extern long AtomicCompareExchange(long*,long, long);
extern char *PLC_ID;

int Simple_C_Call(int val){
  return val+1;
}

int Python_to_C_Call(char toC, char *fromC){
  /* Code called by python should never touch to 
     variables modified by PLC thread directly

     AtomicCompareExchange comes from 
     beremiz' runtime implementation */

  int res = 0;
  if(!AtomicCompareExchange((long*)&Lock, 0, 1)){
    PtoC=toC;
    *fromC=CtoP;
    AtomicCompareExchange((long*)&Lock, 1, 0);
    res=1;
  }
  printf("C code called by Python: toC %d fromC %d\n",toC,*fromC);
  printf("PLC_ID id %s\n",PLC_ID);
  return res;
}

int PLC_C_Call(char fromPLC, char *toPLC){
  /* PLC also have to be realy carefull not to 
     conflict with asynchronous python access */
  if(!AtomicCompareExchange((long*)&Lock, 0, 1)){
      CtoP = fromPLC;
      *toPLC = PtoC;
      AtomicCompareExchange((long*)&Lock, 1, 0);
      return 1;
  }
  return 0;
}
]]></xhtml:p>
  </globals>
  <initFunction>
    <xhtml:p><![CDATA[
]]></xhtml:p>
  </initFunction>
  <cleanUpFunction>
    <xhtml:p><![CDATA[
]]></xhtml:p>
  </cleanUpFunction>
  <retrieveFunction>
    <xhtml:p><![CDATA[
]]></xhtml:p>
  </retrieveFunction>
  <publishFunction>
    <xhtml:p><![CDATA[
if(!AtomicCompareExchange((long*)&Lock, 0, 1)){
    TestInput = CtoP + PtoC + TestOutput;
    AtomicCompareExchange((long*)&Lock, 1, 0);
}
]]></xhtml:p>
  </publishFunction>
</CFile>