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Hello, Mumit Khan wrote: > > Vadim Egorov <egorovv AT 1c DOT ru> writes: > > > > After digging around this problem I think that it concerns win32 SEH > > mechanics. Following code shows the mutations of SEH frame > > list while signals caused by exceptions are processed. > > I suspect the same, but you're much further along than I am. I believe > we have to start mucking with SEH to get things to work correctly, and > the best source of information I've found so far is Pietrek's '97 article > MSJ "A Crash Course on the Depths of Win32 Structured Exception Handling" > that describes the except_handler crap in somewhat gory detail. > > > before longjmp is enough but in general case when other seh frames > > can be involved the task is more complicated. > > I think SEH unwinding should be performed in longjump based on > > target esp value. > > And it gets worse when you're dealing with C++ exceptions on x86-win32, > which currently uses setjmp/longjmp. There are some considerations concerning this problem. First, is the way of stack unwinding. We can simply reinstall last registered SEH frame that is on stack dismissing frames that was registered later. The appropriate frame can be stored in jmp_buf as MS do but I don't think it's a good idea to increase jmp_buf size. For better interoperability with alien code that may use SEH it is necessary to call each of these handlers for unwinding so that they could perform cleanup. It seems possible to do it in MS like way described by Petrek but it will impose some performance overhead on longjmp and on C++ exception handling accordingly. But the problem with signal state still remains - it doesn't get unblocked. If longjmp will perform more or less SEH frame unwinding the same SEH technique can be here - to install additional exception handler while signal handler is being called which would restore signal state if unwinding occurred - but it doesn't look like the best solution. Vadim. -- ********************************************* Vadim Egorov, 1C * ÷ÁÄÉÍ åÇÏÒÏ×,1C egorovv AT 1c DOT ru * egorovv AT 1c DOT ru *********************************************
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