FIX: C2443 Using Structure Member Operand in _asm Block

• The C/C++ Compiler (CL.EXE), used with:
  • Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0, 4.1, 4.2, 5.0
  • Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.52

SYMPTOMS

Under the four conditions described in this article, the following compiler error is generated:

test.cpp(linenumber) : error C2443: operand size conflict

• You're using inline assembly.



• The size of the source operand on an assembly instruction is different from the size of the destination operand.



• The source operand is a member of a structure.



• The PTR operator is used to force the operand to the size required.

RESOLUTION

If you are using C++, declare a reference variable initialized with the structure member. Use the reference variable as the source operand in the assembly instruction as shown in this sample code:

Sample Code

/* Compile options needed: /Tp
*/ 

truct Test
{

 int  nInt;
} test1;

void main(void)
{
__asm  mov  bh, BYTE PTR test1.nInt  /* error occurs here */ 

int & nTest = test1.nInt;   /*  these lines work  */ 

__asm  mov  bh, BYTE PTR nTest   /*  these lines work  */ 
} 

STATUS

This bug was corrected in Microsoft Visual C++, version 6.0.

Additional query words: CPP CXX MASM assembler macro

Keywords : kbVC100bug kbVC150bug kbVC152bug kbVC200bug kbVC210bug kbVC400bug kbVC410bug kbVC420bug kbVC500bug kbVC600fix
Version : winnt:1.0,2.0,2.1,4.0,4.1,4.2,5.0
Platform : winnt
Issue type : kbbug