FIX: CodeView 4.0 and 4.01 Cannot Debug COM Files

ID: Q92868

The information in this article applies to:

Microsoft CodeView for MS-DOS

SYMPTOMS

An attempt to debug a COM file with Microsoft CodeView fails.

CAUSE

Due to an incompatibility between CodeView versions 4.0 and 4.01 and Microsoft LINK versions 5.3 and 5.31.009, the symbol offsets stored in the DBG file differ by 0x100 from the offsets stored in the symbol table in the COM executable file.

RESOLUTION

Build the application using the small memory model during the development phase. Once the application has been debugged, switch to the tiny memory model for the final build.

STATUS

Microsoft has confirmed this to be a problem in CodeView versions 4.0 and 4.01 for MS-DOS. This problem was corrected in CodeView version 4.1 for MS-DOS.

MORE INFORMATION

COM files are built using the tiny memory model. A COM file combines its logical code and data segments into one physical segment. Because the debugging information that CodeView requires cannot fit in the physical segment, is it is placed into a separate DBG file.

Additional query words: 4.00

Keywords : kb16bitonly
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