FIX: Duplicate Source Files Cause Breakpoint Failures

The information in this article applies to:

• The Integrated Debugger, included with Microsoft Visual C++, 32-bit Edition, version 2.0, 2.1, and 4.0

SUMMARY

When the same source file (or a copy with the same name in a different directory) is included in both a DLL and its calling application, the debugger can become confused about which module in memory to set breakpoints in. For example, a breakpoint set in the source file belonging to the DLL may be hit in the DLL or in the application's copy of the source file, and the module in which the breakpoint is hit may change from one debugging session to another.

WORKAROUND

The best solution is to not use source files that have the same name in the DLL and in its calling application. If you can't avoid it, try using the context operator to resolve the breakpoint conflict. To do this, specify both the source file and the EXE or DLL name in the breakpoint location field of the Breakpoints dialog box using this syntax:

   {,source.cpp,target.exe} .line_number

   -or-

   {,source.cpp,target.dll} .line_number

NOTE: This workaround may not always be successful. If it doesn't work, you must either rename one of the source file copies or live with the errant breakpoint behavior.

MORE INFORMATION

For additional information on the purpose and use of the context operator, refer to the "Using Breakpoints" section in the "Using the Debugger" chapter of the Visual C++ Books Online "Visual C++ User's Guide." Specifically, in Visual C++ 2.0, refer to the "General Syntax for Breakpoint Locations" entry in the "Using Breakpoints" section; in Visual C++ 4.0, refer to the "Advanced Breakpoint Syntax" entry of the "Using the Breakpoints Dialog Box" in the "Using Breakpoints" section.