PRB: CodeView Skips Over a Line of Source Code

• Microsoft CodeView for MS-DOS, versions 2.2, 3.0, 3.11, 3.14, 4.0, 4.01, 4.05, 4.1
• Microsoft CodeView for OS/2, versions 2.2, 3.0, 3.11, 3.12, 3.5
• Microsoft CodeView for Windows, versions 3.0, 3.05, 3.06, 3.07, 4.0, 4.01, 4.1
• Microsoft CodeView for Win32s, version 4.25

SYMPTOMS

CodeView does not recognize a breakpoint set in an application. If you run the program, execution does not stop on the breakpoint. If you single-step through the code, CodeView steps past the specified line. This problem also occurs in the QuickC and Visual C++ integrated debuggers.

CAUSE

This behavior occurs because CodeView is line-based and the C compiler is token-based.

RESOLUTION

This restriction is inherent in the CodeView design. To work around this behavior, select mixed source code and assembly language mode and place the breakpoint on the correct line of assembly language code.

MORE INFORMATION

The following sample code can be used to demonstrate this problem.

Sample Code

   /*
    * Compile options needed: /Zi /Od
    */

   int i, j, k, l;

   void main(void)
   {
      for (i = 0; i < 20; i++)
      {
         j = 0;
         for (k = 0; k < 20; k++)
            if (j == 0)
               break;

         j = 1; /*** set breakpoint here ***/
      }

      l = 0;
   }

Keywords          : CvwIss kb16bitonly kbcode
Version           : 2.2 3.0 3.11 3.14 4.0 4.01 4.25
Platform          : MS-DOS OS/2 WINDOWS
Issue type        : kbprb