First member of struct not visible in VS debugger

Question

I am a new bee of assembly language. When i am learning to write a struct, strange things happened.

This is the struct i define

User struct 
    name byte 20 dup(0)
    password byte 10 dup(0)
    more byte "bbbbbbbbbbbbbbbbbbbbbbbbbbbb"
User ends

this is how i declare a variable

user1 User <"chi","fan">

but when i inspect variable user1 in visual studio 2019, i cant see the first member of struct name

close inspect window:

Memory window:

my full code of data.asm

Employee struct
    IdNum byte "000000000"              ; 9
    LastName byte 30 DUP(0)             ; 30
    ALIGN word                          ; 
    Years word 0                        ; 2
    ALIGN dword                         ; 
    SalaryHistory dword 0,0,0,0         ; 16
Employee ends     


Employee2 struct
    IdNum byte "000000000"              ; 9
    LastName byte 30 DUP(0)             ; 30
    ALIGN word                          ; 
    Years word 0                        ; 2
    ALIGN dword                         ; 
    SalaryHistory dword 0,0,0,0         ; 16
Employee2 ends    


User struct 
    name byte 20 dup(0)
    password byte 10 dup(0)
    more byte "bbbbbbbbbbbbbbbbbbbbbbbbbbbb"
User ends

user1 User <"chi","fan">
worker4 Employee <"888","555">
worker2 Employee2 <"aaa","bbb">

my full code in main.asm

.386
.model flat,stdcall
.stack 4096
ExitProcess proto,dwExitCode:dword

.data
    include data.asm
.code
main PROC
  mov worker4.SalaryHistory, 1000H        ;
                                          ; 

  invoke ExitProcess,0
main ENDP
END main

environment: windows,visual studio 2019

user_3857942 · Answer

TL;DR: In modern versions of MASM (including the versions in Visual Studio) a line beginning with name is effectively ignored.

NAME is a reserved word in MASM. Versions of MASM in Visual Studio process the NAME directive as taking a string, but these modern versions of MASM ignore the results of the directive. NAME is a directive that exists to allow better source compatibility with earlier versions of MASM.

Because of this a line that starts with NAME like:

name byte 20 dup(0)

is essentially ignored. This is why it doesn't appear in the debugger, nor can you reference it with something like:

mov user1.name, 'c'

The result of this should be that name is an undefined symbol.

Solutions:

rename the name member to something like uname or any other name that isn't a MASM reserved word.
Use the NOKEYWORD option to tell MASM that you want to override name as a reserved word. Add this to the top of data.asm (or main.asm)
```
OPTION NOKEYWORD:
```
This tells MASM not to consider NAME as a reserved word. This should prevent the unwanted behaviour of MASM ignoring an entire line that starts with NAME.

First member of struct not visible in VS debugger

1 Answers