FIX: Value of @FileName Truncated If File Has Short Extension

The information in this article applies to:

• Microsoft Macro Assembler for MS-DOS, version 6.0
• Microsoft Macro Assembler for OS/2, version 6.0

SYMPTOMS

The predefined symbol @FileName is designed to represent the base name of the current assembly file. However, if you use the /Ta command-line option with the Microsoft Macro Assembler (MASM) version 6.0 to assemble a file that does not have a three letter extension, then the value of @FileName will not be the complete base name of the file.

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

The assembler normally requires all files to have a .ASM extension. This can be changed with the /Ta option that allows any file to be assembled, regardless of its extension. A side-effect of using /Ta is that if the filename does not have a three letter extension, then the value of the @FileName predefined equate will be truncated by one character for each character less than three in the extension.

The sample code below may be used to illustrate this problem. If you save the file as TEST.ASM and assemble with just /c, then the assembler correctly echoes TEST as the base name of the file. If you change the name to TEST.AS and assemble with /c and /Ta TEST.AS, the value of @FileName that is echoed is just TES. Similarly, renaming the file to TEST.A results in only TE being echoed.

Sample Code

; Assemble options needed: /c /Ta TEST.AS

.MODEL small

.CODE % echo @FileName END