Q58718: CVPACK May Lose Type Information in Large Files

Article: Q58718
Product(s): See article
Version(s): 2.01 3.01 | 2.01 3.01
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | s_cvpack s_codeview | mspl13_basic
Last Modified: 5-FEB-1991

Certain type information such as that required to expand a structure
using the "?? <structurename>" command in CodeView can be lost in
large files when using CVPACK.

Running CVPACK on very large executables may remove such information
from the file. Before running CVPACK, internal information can be
viewed and members can be expanded on structures; after CVPACK, only
the structure's address is viewable.

The reason this occurs is that CVPACK is stripping out information
that CodeView needs to correctly display pointers to far data.

In this case, CodeView attempts to provide information on the pointers
to far data in the structure, but the information it gives is not
correct. Observing the change in the structure's segment address
before and after using CVPACK shows that this address changes while
the offset address remains the same. Therefore, the correct
information cannot be displayed, and CodeView emits a warning beep
instead of showing the expanded structure elements.

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