Q32778: C4001 and C4074 "Function Given File Scope" Warnings

Article: Q32778
Product(s): See article
Version(s): 5.00 5.10 6.00 6.00a | 5.10 6.00 6.00a
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | | mspl13_c
Last Modified: 31-JAN-1991

When compiling at warning level 4 (/W4), with language extensions
enabled, a function prototype placed within a function will cause the
compiler to generate the following warning:

   C4001 nonstandard extension used - 'function given file scope'

According to the ANSI standard, functions cannot be declared with
block scope; they must appear at file scope. The warning indicates
that allowing the placement of the function prototype inside the block
is an extension to the C language, and the compiler will behave as
though the function was declared at file scope. The warning can be
avoided by placing the function prototype outside the function.

With C versions 5.10 and earlier, this warning occurs at warning level
3 (/W3) and appears as follows:

   C4074 non-standard extension used - 'function given file scope'

The sample program below demonstrates this warning.

Sample Code
-----------

void main (void);
void main (void)
 {
 void foo(int x);
 }

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