DOCUMENT:Q70249  06-MAY-2001  [masm]
TITLE   :Max Identifier Length May Cause Mixed C/MASM Conflict
PRODUCT :Microsoft Macro Assembler
PROD/VER::5.1,5.1a
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft Macro Assembler (MASM), versions 5.1, 5.1a 
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SUMMARY
=======

The Microsoft Macro Assembler (MASM) versions 5.1 and 5.1a allow identifiers to
have a length of 31 characters. The Microsoft C Compiler versions 5.1, 6.0, and
6.0a also allow identifiers to have a length of up to 31 characters. However,
the C compiler adds an implied leading underscore, which may make the total
length of an identifier 32 characters.

The above limits may cause a problem when performing mixed-language programming
where a C identifier that is 31-characters long needs to be recognized by a
Macro Assembler module. The C identifier of 31 characters becomes 32 characters
because of the added leading underscore, and the assembler can only recognize 31
characters. If this occurs, a "L2029: unresolved external" error will be
generated by the linker when it does not locate a symbol with the truncated
name.

MORE INFORMATION
================

To get the assembler routine to match the C identifier of 31 characters, you can
do one of the following:

1. Use the .MODEL directive and specify the C language type. For example:

         .MODEL small,c  ; The C language type specifies C conventions

   The C language type specifies C naming and calling conventions. It will allow
   the use of a 31-character identifier and also add the implied leading
   underscore.

2. Modify the C program to shorten the length of the variable's name.

3. Update to Macro Assembler version 6.0. Identifiers may be up to 247
   characters long with version 6.0.

Additional query words: kbinf 5.10 5.10a

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Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM510 kbMASM510a
Version           : :5.1,5.1a

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