Re: why UI gets hangs
Joseph M. Newcomer wrote:
On Mon, 24 Mar 2008 06:31:44 GMT, Dan Bloomquist <public21@lakeweb.com> wrote:
UINT Thread( LPVOID pParam )
{
TS& strct= *static_cast<TS*>( pParam );
for( long i= 0; ; ++i )
{
//if( strct.bTReady )
{
strct.strT.Format( _T("Test This %d"), i );
::PostMessage( *strct.pDlg, ID_CHECK_THREAD, 0, 0 );
****
This is truly weird, because you are using a shared variable and bizarre simulated
locking, and there is no need to do ANY of this, because you can pass a pointer in the
message itself! This means that you aren't going to lose anything, and you don't need to
do ugly polling loops!
Hi Joe,
I think you have misunderstood my objective.
UINT Thread( LPVOID pParam )
{
....
for( long i= 0; ; ++i )
//This is the worker loop, it is doing real work.
{
...
//Now it has progress data for the GUI thread
//if that thread is ready for another message
//it will post it.
if( strct.bTReady )
{
strct.strT.Format( _T("Test This %d"), i );
::PostMessage( *strct.pDlg, ID_CHECK_THREAD, 0, 0 );
strct.bTReady= false;
}
}
}
I wouldn't trust this code to work correctly in a multiprocessor.
Does this still apply?
sending thread:
WaitForSingleObject(strct.semaphore, INFINITE);
That's what semaphores are for. The code you show cannot be trusted to be correct in all
situations, and by using polling, you are wasting significant amounts of energy.
My objective was an example of 'not' blocking the thread and keeping the
GUI updated. In that light, do you see a problem with the way I use the
semaphore strct.bTReady?
Best, Dan.