Article: Q74924
Product(s): Microsoft Macro Assembler
Version(s): MS-DOS:5.10,5.10a,6.0
Operating System(s):
Keyword(s):
Last Modified: 04-MAY-2001
-------------------------------------------------------------------------------
The information in this article applies to:
- Microsoft Macro Assembler (MASM), versions 5.10, 5.10a, 6.0
-------------------------------------------------------------------------------
SUMMARY
=======
With the Microsoft Macro Assembler (MASM), if a structure type is declared but
no instance of the structure is ever defined, the assembler will still permit
access to the structure.
This is expected behavior for the assembler. A reference to a structure field in
this manner is equivalent to taking the offset of the field from the beginning
of the structure.
MORE INFORMATION
================
The sample code below illustrates this situation. The example declares an
"animal" structure type, but does not define an instance of the structure. A
reference to this structure type is then made in the following line:
mov ax, animal.dog
As described above, the reference to animal.dog just generates the offset of the
field, dog, from the beginning of the structure; therefore, this line is
effectively the same as the statement "mov ax, 2".
Sample Code
-----------
; Assemble options needed: none
.MODEL SMALL
animal struc
cat dw 11
dog dw 12
animal ends
.CODE
start: mov ax, @data
mov ds, ax
mov ax, animal.dog
END start
Additional query words: kbinf 5.10 5.10a 6.00 6.00a 6.00b
======================================================================
Keywords :
Technology : kbMASMsearch kbAudDeveloper kbMASM600
Version : MS-DOS:5.10,5.10a,6.0
=============================================================================