FIX: Incorrect CV Info for Local Structure in MASM 6.0

MS-DOS           | OS/2

The information in this article applies to:

• Microsoft Macro Assembler for MS-DOS, versions 6.0, 6.0a, and 6.0b
• Microsoft Macro Assembler for OS/2, versions 6.0, 6.0a, and 6.0b

SYMPTOMS

When a program that contains a local structure but no global structures of the same type is assembled with the Microsoft Macro Assembler (MASM), and that variable is watched with the Microsoft CodeView (CV) debugger, CodeView will report that the variable has no type.

CAUSE

The CodeView information generated by MASM for that local structure is not correct.

RESOLUTION

Declare a dummy global structure of the same type.

STATUS

Microsoft has confirmed this to be a problem in MASM versions 6.0, 6.0a, and 6.0b. This problem was corrected in MASM for MS-DOS version 6.1.

MORE INFORMATION

The following sample demonstrates the problem. Bring the .EXE into CodeView and begin stepping through. After stepping into procedure "func", the local window has:

   <no type> result

   +struct sample result

Sample Code

; Assemble options needed: /Zi

.MODEL small, C

sample STRUC

    x1 DW 1
    x2 DW 2

.STACK 4096

.DATA ;global sample <>

.CODE func PROC near

    LOCAL result:sample

    mov result.x1, 0
    mov result.x2, 0
    ret

start:

    .startup
    call func
    .exit 0