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Q66782: Fastcalls (/Gr) Incompatible with Disabled MS Extensions (/Za)

Article: Q66782
Product(s): See article
Version(s): 6.00 6.00a | 6.00 6.00a
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | buglist6.00 buglist6.00a _fastcall | mspl13_c
Last Modified: 15-NOV-1990

The Microsoft C versions 6.00 and C 6.00a compiler options /Za and /Gr
are not currently compatible. /Gr enables the register calling
convention for passing function parameters in registers, and /Za
disables Microsoft-specific extensions to the C language. In C 6.00
and C 6.00a, the register calling convention relies on Microsoft
extensions being enabled (/Ze).

If you try to specify both /Gr and /Za, the compiler will halt with
the following error:

   Command line error D2020 : -Gr option requires extended
   keywords to be enabled (-Ze)

Removal of this limitation is being considered for a future release of
the C compiler.

Microsoft has confirmed this to be a problem in C versions 6.00 and
6.00a. We are researching this problem and will post new information
here as it becomes available.

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