Test multithreading with a simple example

multithread_simple.cpp

#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <process.h>

#ifdef WIN32
#define USING_OBDLL
#endif

#include <openbabel/babelconfig.h>
#include <openbabel/obconversion.h>
#include <openbabel/mol.h>
#include <openbabel/parsmart.h>

#define MAX_THREADS  4

HANDLE  hScreenMutex;                // "Screen update" mutex
int     ThreadNr;                    // Number of threads started 

using namespace OpenBabel;

struct ThreadData {
  ThreadData(OBSmartsPattern* _pat, OBMol* _mol) : pat(_pat), mol(_mol) {};
  OBSmartsPattern* pat;
  OBMol* mol;
};

void DoSearch(void* threadData)
{
  ThreadData* td = (ThreadData*)threadData;

  OBSmartsPattern* pat = td->pat;
  OBMol* mol = td->mol;
  std::vector<std::vector<int> > mlist;
  pat->Match(*mol, mlist);

  //WaitForSingleObject(hScreenMutex, INFINITE);
  //printf("Finishing thread %d\n", ThreadNr);
  //ReleaseMutex(hScreenMutex);

  InterlockedDecrement((LONG*)&ThreadNr);
}

void StartThreads(void) // Dispatch and count threads.
{
  obErrorLog.StopLogging();
  OBConversion conv;
  conv.SetInFormat("smi");
  OBMol *molA = new OBMol();
  OBMol *molB = new OBMol();
  conv.ReadString(molA, "C");
  conv.ReadString(molB, "CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC");
  OBSmartsPattern *patA = new OBSmartsPattern();
  patA->Init("[#6]");
  
  ThreadData *tdA = new ThreadData(patA, molA);
  ThreadData *tdB = new ThreadData(patA, molB);

  ThreadNr = 2;
  _beginthread(DoSearch, 0, tdA);
  _beginthread(DoSearch, 0, tdB);

  while (ThreadNr > 0) {
    Sleep(250);
  }

}

int main() // Thread One 
{
  // Create the mutexes and reset thread count.
  hScreenMutex = CreateMutex(NULL, FALSE, NULL);  // Cleared 
  ThreadNr = 0;

  StartThreads();

  // All threads done. Clean up handles.
  CloseHandle(hScreenMutex);
  getchar();
}