Hello guys

I am learning VC++ 6.0 which is not an easy language at all.  I have just learnt how to create threads using AfxBeginThread( ).  I have listed here my own example program (multitask.cpp) to show the use of threads.  Hopefully the program is simple and self explannary to eveybody.  I would like to share what I have learnt!!  I would be grateful if anybody can comment on my program and may suggest a way to improve it.

All the best

Chong

P.C.

If anybody wants another version of this program which uses _beginthread() instead of AfxBeginThread(), let me know.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 

// multitask.cpp

// Note : Before building for an executable file, do the following (after compiling):
//   (1) Choose the [Project] menu
//   (2) Choose [Settings]
//   (3) Choose [General] and select [Use MFC in a Static Library]
//       for [Microsoft Foundation Classes].

// Note that, when the main application exits/terminates, it kills all its
// threads.

// the test.txt file contains "abcdefghi" 

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <io.h>

#include <Afxwin.h> // for CWinThread

#include <windows.h> // for Sleep()
#include <winbase.h> // for Sleep()

UINT ThreadFunc(LPVOID pParam);

class MsgFromFile {
private:
 int fp; char buf[100];
public:
 BOOL OpenDataFile() {
  if ((fp=open("test.txt",O_RDONLY))<0) return FALSE;
   else return TRUE;
 }
 BOOL ReadDataFile(){
  int nbytes, k =0;
  while (TRUE){
   if ((nbytes=read(fp,buf,3-k))<0) return FALSE;
   else if (nbytes == 0) {buf[k]=NULL;return TRUE;}
   else if ((k=k+nbytes)<3) continue;
   break;
  }
  buf[k]=NULL;
  return TRUE;
 }
 void WriteMsg(){ printf("Thread:%s\n",buf);}
};

char gMsg[100]; // global to the threads too!

main()
{
 MsgFromFile a;
 int iPriority = 0;
 CWinThread* ThreadID[2];

 a.OpenDataFile();
 a.ReadDataFile();
 printf("The main application: ");
 a.WriteMsg();

 strcpy(gMsg,"This works");

 //Start the independent threads
 ThreadID[0] = AfxBeginThread(ThreadFunc,(LPVOID)&a,iPriority);
 ThreadID[1] = AfxBeginThread(ThreadFunc,(LPVOID)&a,iPriority);
 
 //ThreadID[0]->SuspendThread(); //This suspends the thread ThreadID[0].It does not kill
         //the thread.
 //ThreadID[0]->ResumeThread(); //This resumes the thread ThreadID[0].

 //Wait until the threads have died.
 HANDLE hthread;
 hthread= ThreadID[0]->m_hThread;
 WaitForSingleObject(hthread,INFINITE);
 hthread = ThreadID[1]->m_hThread;
 WaitForSingleObject(hthread,INFINITE);

 printf("The main application: "); a.WriteMsg();
 printf("The main application(parent) exits\n");
 Sleep(10000); //Sleep for 10 seconds

} // main

UINT ThreadFunc(LPVOID pParam)
{

 MsgFromFile* myfile = (MsgFromFile*)pParam;

 if (!(myfile->ReadDataFile())) {
  printf("Thread: failed to read the data file\n");
  //exit(-1); //This kills the main application too!
  return 0;
 } // if

 myfile->WriteMsg();
 printf("Thread: %s \n", gMsg);

 Sleep(5000);
 printf("Thread: exits\n");

 return 0;
} // ThreadFunc
+++++++++++++++++++++++++++++++++++++++++++++++++++