Difference between revisions of "Ctrl C"

Revision as of 15:56, 6 June 2007

On Windows, the handling of SIGINT (aka Ctrl+C for a DOS prompt) is done in a different thread than the running thread. Which means that the current runtime cannot handle it properly without failing, since it throws an exception in the wrong thread. This problem is even more visible in a multithreaded application.

I've posted a question on the Microsoft newsgroups and here is the discussion thread. The interesting part of this is a reference to another discussion thread where they propose a solution. A quick summary is the following code:

// Suspend the thread
SuspendThread (hSorryThread);
 
	// Get the thread's suspended context and then
	// update it to point to the cleanup routine ...
ctx.ContextFlags = CONTEXT_CONTROL | CONTEXT_INTEGER;
ctx.Eip = (DWORD) CleanupProc;                    // You define this
SetThreadContext (hSorryThread, &ctx);
 
	// and resume the thread with the new context
ResumeThread (hSorryThread);
 
	// Note that the sketch above assumes that CleanupProc() takes no arguments and
	// will exit the thread. It had better because the few lines above don't do
	// anything with the stack.

This needs to be investigated.