MSM9109002: Nested Structures May Hang Macro Assembler 6.0

ID Number: Q76217

6.00 | 6.00

MS-DOS | OS/2

buglist6.00 fixlist6.00a

Summary:

PROBLEM ID: MSM9109002

SYMPTOMS

Nested structures may cause the Microsoft Macro Assembler (MASM)

version 6.0 to hang when one structure contains a field of the

type of another structure and it is initialized. The code below

demonstrates the problem more clearly.

RESOLUTION

Pad the initializer to make it the size declared. In the sample

code below, padding the initializer for the member called People to

three characters corrects the problem.

STATUS

Microsoft has confirmed this to be a problem in MASM version 6.0.

This problem was corrected in MASM version 6.0a.

More Information:

In the sample code, notice that the structure member Nme has a length

of three bytes. However, the structure called People initializes its

Nme member to 'R', which is one character instead of three. This

produces the problem.

Under DOS, the assembler logo will appear, and the system will hang.

Under OS/2, the following message appears:

The process has stopped.

The software diagnostic code (trap number) is 013.

Sample Code

-----------

; Assemble options needed: /c

.MODEL SMALL

aStruct STRUCT

Nme BYTE 3 DUP (?)

aStruct ENDS

bStruct STRUCT

People aStruct <'R'>

; Replace above line with the following line to work around problem.

;

; People aStruct <'R '> ; 'R' is followed by two spaces

bStruct ENDS

.DATA

Crash bStruct { }

END

Additional reference words: LOCK HANG STRUCT