AutoCAD crashes when using _fcloseall()

by Fenton Webb

Issue

AutoCAD is crashing when using _fcloseall() function in an ARX application. The error message is: ‘Internal error:SHLOAD SHSEEK 2‘. If I use fclose() function instead of _fcloseall() function, then the problem does not occur.

Solution

First, you must make sure you link your ARX application using the C Runtime Library "Multithreaded DLL" , this is the recommended setting. AutoCAD is linked "Multithreaded DLL" so your ARX application uses the same instance of the C Runtime Library as AutoCAD.

This also means, both ACAD and your application share the same file pointers. If you call _fcloseall() in your application, you close all files that ACAD.EXE has opened.

The workaround is to NOT call _fcloseall(), or to compile & link your application "Multithreaded". In that case, your application will have its own C Runtime Library statically linked to your DLL