1.00 1.50
WINDOWS
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The information in this article applies to:
- The Microsoft C/C++ Compiler (CL.EXE), included with:
Microsoft Visual C++ for Windows version 1.0
- The Visual Workbench, included with:
Microsoft Visual C++ for Windows, versions 1.0 and 1.5
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SYMPTOMS
========
When starting an application for debugging in CodeView for Windows or
in the Visual WorkBench debugger, a General Protection Fault occurs
in SHW0.DLL at 0001:83BA.
CAUSE
=====
This is actually the result of two bugs, one in the Microsoft C/C++
compiler, version 8.0, and one in the debuggers (CodeView for Windows
and the Visual WorkBench debugger).
The compiler bug occurs when using the #pragma code_seg preprocessor
directive to specify more than one segment in a single source file.
C/C++ for MS-DOS version 8.0 will generate incorrect CodeView line-
number information when the object module is compiled with the
optimizing compiler (/f-). The sample code shown below illustrates
this problem.
The problem with the debuggers occurs when an application, either an
executable or a dynamic link library, has greater than 64K of type
information. CodeView for Windows versions 4.0, 4.01, 4.05, and 4.10
and the Visual Workbench debugger versions 1.0 and 1.5 will cause a
General Protection Fault when loading the types table.
RESOLUTION
==========
Since this is a two-part problem, it requires a two-part resolution. The
proper line number information can be generated by using the fast compiler.
Use of the fast compiler can be forced by specifying the /f compiler
switch. The debugger memory allocation bug can be worked around by reducing
the amount of type information. Microsoft Knowledge Base article Q112335
deals with a similar problem which causes CVPack to generate a CK4009
error. This article also details methods for reducing the amount of type
information.
STATUS
======
Microsoft has confirmed this to be a bug in the Microsoft products
listed at the beginning of this article. The compiler problem was corrected
in C/C++ Compiler version 8.0c, which is included with Visual C++ for
Windows, version 1.5. Microsoft is researching the debugger problem and
will post new information here in the Microsoft Knowledge Base as it
becomes available.
Sample Code
-----------
/* Compile options needed: /c /Od /f- /AL /Zd
*/
#include <stdio.h>
#pragma code_seg("test_seg")
void func(void)
{
printf("This is func().\n");
}
#pragma code_seg("test_seg1")
void func1(void)
{
_asm nop
printf("This is func1().\n");
}
#pragma code_seg("test_seg2")
void func2(void)
{
printf("This is func2().\n");
}
Additional reference words: 8.00 1.00 1.50 4.00 4.01 4.05 4.10
KBCategory: kbtool kbbuglist kbfixlist
KBSubcategory: TlsMisc