Re: Unexpected reentrancy on Wait,etc...

Hi Jake,

Usually some code using locks can be reworked such that each thread works
with private copies of data only, returning data using a centralized queue,
with only the centralized queue being thread safe (using locks or other
techniques).

If you don't mind your reentrant function failing, set a boolean field to
true on entry of the function, and set it to false in a finally statement at
the end of the function (the body being in a try). Then add a check to the
top of the function to bail out if you are already executing the function.
That is the standard non-reentrancy guard.

Regards,
Frank Hileman

check out VG.net: http://www.vgdotnet.com
Animated vector graphics system
Integrated Visual Studio graphics editor

"jaket" <jtummond@xxxxxxxxx> wrote in message
news:1194046798.871695.228490@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hello,

I have run into a serious reentrancy problem. It appears from a stack
trace that lock, WaitOne and Thread.Join do some servicing of the
message queue. Here is the setup:

The GUI thread uses a combination of Application.Idle and a timer to
simulate the old MFC OnIdle. The Idle handling will periodically pick
up some work that requires executing some non-reentrant code. This
code uses several locks to synchronize with other threads.

Another background worker thread is calling thru the Application's
API. The API must use Control.Invoke using the MainForm to marshal
the calls to the GUI thread. It also calls the non-reentrant code.

While GUI thread is waiting on a lock (I presume that it is already
held by a 3rd thread), the Control.Invoke can occassionaly slip thru
and cause reentrancy. Anyone familiar with the perils of DoEvents
will understand why this is a major problem.

Any suggestions?

Sincerely, Jake



.

Relevant Pages

  • Re: Unexpected reentrancy on Wait,etc...
    ... This doesn't solve the general problem that the GUI can ... Usually some code using locks can be reworked such that each thread works ... with private copies of data only, returning data using a centralized queue, ... up some work that requires executing some non-reentrant code. ...
    (microsoft.public.dotnet.framework.clr)
  • Re: Unexpected reentrancy on Wait,etc...
    ... The GUI thread is an STA thread. ... thread's message queue. ... Usually some code using locks can be reworked such that each thread works ...
    (microsoft.public.dotnet.framework.clr)
Loading