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Q44006: CodeView Requires PUBLIC to Trace MASM Program in Source Mode

Article: Q44006
Product(s): See article
Version(s): 2.20
Operating System(s): MS-DOS
Keyword(s): ENDUSER | H_MASM | mspl13_basic
Last Modified: 3-MAY-1989

A MASM program that runs perfectly from a DOS prompt refuses to trace
in source mode inside of CodeView. The program single-steps in
assembly mode, but an attempt to trace into the code in source mode
results in the program terminating upon reaching the first data
declaration.

In addition, the program does not come up in source mode when CodeView
is started, but can be changed into source mode with "View" "Source".

This problem happens when the code and data segments are not declared
as "PUBLIC". The code is valid and executes perfectly inside of
CodeView or from a DOS prompt. However, CodeView cannot follow the
logic at a source level.

A program constructed in the following manner exhibits the symptoms
described above:

TITLE    myprog

StackSeg Segment STACK
.
.
.
DataSeg  Segment DATA
.
.
.
CodeSeg  Segment CODE
.
.
.
END      myprog

However, if the following minor changes are made to the program, and
the segments are declared as "PUBLIC", CodeView can trace through the
program in source mode:

TITLE    myprog

StackSeg Segment STACK
.
.
.
DataSeg  Segment WORD PUBLIC 'DATA'
.
.
.
CodeSeg  Segment WORD PUBLIC 'CODE'
.
.
.
END      myprog

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