Minimize the Possibility of Data Corruption when Exporting a Class

Introduction

This is a very important tip copied from MSDN about DLL class exporting. Although this can be found in MSDN, not too many novice programmers would be aware of it. Hence, I am posting it as a tip.

The complete article can be found here.

Compiler Warning (level 1) C4251

Visual Studio 2010

Other Versions

• Visual Studio 11
• Visual Studio 2008
• Visual Studio 2005
• Visual Studio .NET 2003

'identifier' : class 'type' needs to have DLL-interface to be used by clients of class 'type2'.

To minimize the possibility of data corruption when exporting a class with __declspec(dllexport), ensure that:

• All your static data is accessed through functions that are exported from the DLL.
• No inlined methods of your class can modify static data.
• No inlined methods of your class use CRT functions or other library functions use static data (see Potential Errors Passing CRT Objects Across DLL Boundaries for more information).
• No methods of your class (regardless of inlining) can use types where the instantiation in the EXE and DLL have static data differences.

History

• Tip uploaded: 11^th March, 2012