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IDProjectCategoryView StatusDate SubmittedLast Update
0033834CommunityOCCT:Configurationpublic2024-09-28 16:312024-10-02 08:29
Reportermike.goutrie Assigned Todpasukhi  
PrioritynormalSeveritycrash 
Status newResolutionopen 
PlatformPCOSWindows VC++2022 win32 
Product Version7.8.0 
Summary0033834: Configuration - Access violations when unloading DLL after STEP-/IGES-import
DescriptionFix to metadata:
* OCCT Version is 7.8.1

We use OCCT within a shared library (32 bit DLL) which is dynamically loaded and unloaded with LoadLibrary/FreeLibrary functions.
Our DLL uses OCCT as shared libraries. (But these errors occur even when using static OCC libs).

After Importing an STEP or IGES file, access violation exceptions are raised when unloading the DLL (FreeLibrary).
Sometimes these errors are dropped by the OS (so they are observed only when the debugger is attaced) but sometimes they crash the whole application.

The situation gets much worse if some of the OCCT-Dll's are not unloaded because they are used in other parts of the program. (E.g. we always use some modeling algorithms but the Import/Export is only loaded when needed).

As far as I analyzed the issue it has to deal with the lots of static maps that register types and instances. So I suppose a relation to https://tracker.dev.opencascade.org/view.php?id=33719.
Steps To ReproduceBuild a shared library with:

#include "IGESControl_Reader.hxx"
#include "STEPControl_Reader.hxx"

#include <iostream>
#include <windows.h>

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD ul_reason_for_call,
                       LPVOID lpReserved
                     )
{
    return TRUE;
}

extern "C"
{
   void __declspec(dllexport) _cdecl RunImport(char const* szName)
   {
      std::cerr << "Running Import of " << szName << "\n";

      STEPControl_Reader r;
      IGESControl_Reader ir;
   }
}

and a console application with

#include <iostream>
#include <windows.h>

DWORD ExceptionFilter(unsigned int code, struct _EXCEPTION_POINTERS* ep)
{
   auto addr = ep->ExceptionRecord->ExceptionAddress;
   std::cerr << "ErrorCode = 0x" << std::hex << code << " Address= 0x" << addr << "\n" << std::flush;
   return EXCEPTION_EXECUTE_HANDLER;
}

int main()
{
   auto hXS = LoadLibrary(L"TKernel.dll");
   std::cout << std::hex << "Address of TKernel.dll: 0x" << hXS << "\n";

   while (true)
   {
      __try
      {
            auto h = LoadLibrary(L"TestDll");
            std::cout << "Address of TestDll: 0x" << h << "\n";

            typedef void(*RunImportFunc)(char const*);
            RunImportFunc pRunImport = (RunImportFunc)GetProcAddress(h, "RunImport");
            std::cout << "Address of RunImport: 0x" << pRunImport << "\n";

            if (pRunImport)
            {
               pRunImport("C:\\Testfile.step");
            }

            std::cout << "Unload TestDll\n" << std::flush;
            bool bUnloaded = FreeLibrary(h);
            std::cout << "Unloading result " << std::boolalpha << bUnloaded << "\n" << std::flush;
      }
      __except(ExceptionFilter(GetExceptionCode(), GetExceptionInformation()))
      {
            std::cerr << "ERROR\n" << std::flush;
            break;
      }
   }
}


Let the application run for some seconds an afterusually less than 10 iterations of the while loop an access violation error is thrown.
TagsNo tags attached.
Test case number

Attached Files

  • Testprojects.7z (3,640 bytes)

Relationships

related to 0016210 assignedgka Open CASCADE Static object destroing in the dlclose() conflict 

Activities

mike.goutrie

2024-09-28 16:31

reporter  

Testprojects.7z (3,640 bytes)

dpasukhi

2024-09-28 17:44

administrator   ~0116775

@mike.goutrie unloading is not accepted for OCCT components for now.
The crash is expected. We have some plans to accept unloading, but now it is not supported.

dpasukhi

2024-09-29 22:28

administrator   ~0116776

The issue related with XSBase logic.
We plan to rework it. Unfortunately, it will be later then 7.9

mike.goutrie

2024-10-02 08:29

reporter   ~0116796

@dpasukhi Thank you for the information.
So I will change our application to never unload these DLL's and observe the progress concerning these issues.

Issue History

Date Modified Username Field Change
2024-09-28 16:31 mike.goutrie New Issue
2024-09-28 16:31 mike.goutrie Assigned To => dpasukhi
2024-09-28 16:31 mike.goutrie File Added: Testprojects.7z
2024-09-28 17:44 dpasukhi Note Added: 0116775
2024-09-28 17:44 dpasukhi Category OCCT:Coding => OCCT:Configuration
2024-09-28 17:44 dpasukhi Summary Access violations when unloading DLL after STEP-/IGES-import => Configuration - Access violations when unloading DLL after STEP-/IGES-import
2024-09-29 22:25 dpasukhi Relationship added related to 0033719
2024-09-29 22:25 dpasukhi Relationship deleted related to 0033719
2024-09-29 22:27 dpasukhi Relationship added related to 0016210
2024-09-29 22:28 dpasukhi Note Added: 0116776
2024-10-02 08:29 mike.goutrie Note Added: 0116796