RE: [Dev-C++] Multi-Threading locks up

[Santiago P. C. <San...@yd...>]

Hi Ed,

Talking about the scenario where you show a MessageBox, in this situation=
=20an interval time is created between the launching of each thread, so p=
lease...
- check that each thread has not finished before you press the OK button.=
..
- (if the previous thread is still running) check the execution point whe=
re the previous thread is at when the next thread starts...
- check that the threads are not using static variables for temporary val=
ues or loops...

It seems there is a problem with the concurrent execution of your threads=
=20(when they run simultaneously), please check that they behave without =
problems...

Hope this helps!
Regards,
~Santy

-----Original Message-----
From: dev...@li... [mailto:dev-cpp-users-adm=
in...@li...] On Behalf Of Ed Cottrell
Sent: mi=E9rcoles, 17 de septiembre de 2003 17:59
To: dev...@li...
Subject: [Dev-C++] Multi-Threading locks up


Hi,

I'm working on a multi-threaded database app, which connects to multiple =
databases and does data-mining. The main thread (which includes the Win32=
=20GUI) launches off a user-specified number of threads (say, 10), which =
then do the actually database queries.=20

I've hit a weird snag, though. As written, the threads all start properly=
, but then pause themselves, immediately, or almost immediately (after up=
dating 0 to maybe 500 records, out of several hundred thousand). The prob=
lem isn't on the database server end; it works fine, but reports that the=
=20threads have stopped running queries. Pseudo-code:

...
int i, MyThreads=3D10;
for(i =3D 0; i < MyThreads; i++)
=20   {
=20       //Splits up the work, here, into MyThreads chunks
=20       _beginthread( [the arguments] )
=20   }
...

This is where it gets weird... IF I create a message box first, the threa=
ds start properly AND run until finished! Pseudo-code:=20

...
int i, MyThreads=3D10;
char mymsg[10]
for(i =3D 0; i < MyThreads; i++)
=20   {=20
=20       //Splits up the work, here, into MyThreads chunks
=20       _beginthread( [the arguments] )=20
=20       sprintf(mymsg, "%d", i);
=20       MessageBox(0, mymsg, mymsg, MB_OK);
=20   }=20
...

The ONLY difference is in whether or not I show a message box. Anybody kn=
ow what that's about? Thanks a million!

-Ed
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