<varargs.h> vs. function prototypes

[Tony L. Hansen]

< From: markhall at pyrps5.pyramid.com (Mark Hall)
<	#ifdef __STDC__
<	void foo(char *format, ...)
<	#else
<	void foo(format, va_alist) char *format; va_dcl
<	#endif
<	{
<		va_list ap;
<		#ifdef __STDC__
<			va_start(ap,format);
<		#else
<			va_start(ap);
<		#endif
<		
<		[ ... rest of stuff the same ... ]
<	}

The above form for <varargs.h> usage is wrong. The documentation, and some
implementations, REQUIRE you to declare the function as:

	void foo(va_alist) va_dcl

and then pick off the fixed arguments using va_arg:

		char *format;

		format = va_arg(ap,char*);

Any other usage is non-portable (as portable as you can be using varargs.h,
that is.  :-) )

					Tony Hansen
			    hansen at pegasus.att.com, tony at attmail.com
				att!pegasus!hansen, attmail!tony