FIX: Bitwise OR for Bool& Types Causes Error When Optimized

• Microsoft Visual C++, 32-bit Editions, version 6.0

SYMPTOMS

When using a bitwise OR operation on a bool reference and compiling with optimizations that include /Og (global optimizations), the resulting executable may generate an access violation.

CAUSE

The current implementation of a bool is an 8-bit value. The OR operation with /Og on a bool reference operates on a 32-bit value.

RESOLUTION

Do not use bitwise operators with bool references. Use bool values instead.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

This bug was corrected in Visual Studio 6.0 Service Pack 3. For more information about Visual Studio service packs, please see the following articles in the Microsoft Knowledge Base:

Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

Q194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed

MORE INFORMATION

Steps to Reproduce Behavior

// Workaround: replace the bool& with bool
void func(bool& boolref, float a, float b)
{
	boolref |= (a == b);
}

void main()
{
	bool b1 = true;

	float f1 = 2.0;
	float f2 = 2.0;

	func(b1,f1,f2);

} 

Additional query words:

Keywords : kbservicepack kbVC600fix kbVS600sp2 kbVS600SP1 kbVS600sp3fix
Version : winnt:6.0
Platform : winnt
Issue type : kbbug