Article ID: 150884
Article Last Modified on 7/5/2005
APPLIES TO
- Microsoft Visual C++ 4.0 Standard Edition
- Microsoft Visual C++ 4.1 Subscription
This article was previously published under Q150884
SYMPTOMS
Using /O1 (minimize size) or /O2 (maximize speed) causes a C1001 error in a try block with the following error message:
Additionally, C++ exception handling must be enabled (/GX). If the warning level is set to 4 (/W4), C4702 (unreachable code) warnings are issued before the C1001 fatal error.
CAUSE
The cause of the problem is having both /Og (global optimizations) and inline function expansion /Ob1 (Only __inline) or /Ob2 (Any Suitable) compiling. /O1 and /O2 are both compound switches, including /Og and /Ob1.
RESOLUTION
Disable either global optimizations (/Og-) or inline function expansion (/Ob1- or /Ob2-). Please see the More Information section below.
STATUS
Microsoft has confirmed this to be bug in the Microsoft products listed at the beginning of this article. This bug was corrected in Visual C++ 32-bit Edition version 4.2.
MORE INFORMATION
The following code reproduces the error when compiled:
// Compile option needed are: /GX, /W4, and /O1(minimize size)
// or /O2 (maximize speed)
struct A
{
~A(){}
};
struct B
{
A a;
};
void main(void)
{
try // line 17
{
B *pB = new B[4];
delete [] pB; // line 20, warning C4702: unreachable code
}
catch(...)
{
}
}
The following error message is generated:
Compiling from command line with both /Og (global optimizations) and in-line function expansion, /Ob1(Only __inline) or /Ob2 (Any Suitable), reproduces the error. For instance, using:
cl /Og /Ob1 /GX /W4 test.cpp
Compiling with the following switch settings in command line does not produce errors:
cl /Og /GX /W4 test.cpp
- or -
cl /Ob1 /GX /W4 test.cpp
One workaround when using /O1 or /O2 in Developer Studio is to disable In-line function expansion (Build:Settings, C++ Tab, Optimizations category). Another workaround is to disable global optimizations. To accomplish this, choose Custom for the type of optimization (Build:Settings, C++ Tab, Optimizations category). Check all categories that apply, but do not check global optimizations. This behavior is similar to using the components of /O1 or /O2 and eliminating /Og). An additional method is to leave /O1 or /O2 intact and manually add /Og- to the Project Options.
Additional query words: kbVC400bug 4.00 4.10 4.20 vcfixlist420 CPPIss
Keywords: kbbug kbfix kbcpponly kbcompiler KB150884
