Thread

[bigSteve]

Hello All,

I am learning how to use the TThread class to create
another thread from my mainform. Essentially, I am writing
a file/folder search program that uses a recursive function
called vSearch_Folder( ....) which takes 4 parameters. I am calling
this function within the Execute method of the thread object, using the code below:-


void __fastcall searchThread::Execute()
{
FreeOnTerminate = false;

// call search functions
mainform->vSearch_Folder(THREAD_FolderPath,
THREAD_SearchString,
THREAD_iSwitch,
pTHREAD_iCounter);

// free up memory for thread object
FreeOnTerminate = true;
}

I am using a flag, FreeOnTerminate, to determine when the thread
has finished execution. (ie when the recursive function has finished.)
THe value of this flag is determined in mainform by calling inline

bool bGetThreadStatus(void){return FreeOnTerminate;};

which is declared in the class derived from TThread.



Q. Is there a better way to determine when a thread finishes execution ?

Thanks,


bigSteve

[Fordy]

Originally posted by bigSteve
Hello All,

I am learning how to use the TThread class to create
another thread from my mainform. Essentially, I am writing
a file/folder search program that uses a recursive function
called vSearch_Folder( ....) which takes 4 parameters. I am calling
this function within the Execute method of the thread object, using the code below:-


void __fastcall searchThread::Execute()
{
FreeOnTerminate = false;

// call search functions
mainform->vSearch_Folder(THREAD_FolderPath,
THREAD_SearchString,
THREAD_iSwitch,
pTHREAD_iCounter);

// free up memory for thread object
FreeOnTerminate = true;
}

I am using a flag, FreeOnTerminate, to determine when the thread
has finished execution. (ie when the recursive function has finished.)
THe value of this flag is determined in mainform by calling inline

bool bGetThreadStatus(void){return FreeOnTerminate;};

which is declared in the class derived from TThread.



Q. Is there a better way to determine when a thread finishes execution ?

Thanks,


bigSteve

Yes.........unless you mark FreeOnTerminate as a "volatile", there's no guarantee that your code will work. 1 standard unprotected variable accessed by 2 threads is often a recipie for disaster!

A better way is for you to use one of window's thread sync objects...Events (with CreateEvent()) or Mutexes (CreateMutex()) are good possibilities depending on what you want to do