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From: sm@gator.cacs.usl.edu (Srinivas Madhur)
Newsgroups: comp.unix.questions
Subject: problem with varargs
Keywords: varargs, SunOS
Message-ID: <5810@rouge.usl.edu>
Date: 26 Mar 90 00:25:45 GMT
Sender: anon@rouge.usl.edu
Organization: The Center for Advanced Computer Studies, USL
Lines: 48

Hi netters!

I am having a problem with varargs (both on Sun 4.0 and 4.3BSD).
The example program given in the man page shows that after all
the parameters passed are read, next time va_arg is called, the
return value will be NULL which can be used as a sentinel.
I am getting the NULL value if there is *no other variable* 
defined after the actual parameter or if the paramter passed to 
the function is global. Is there any known problem with varargs
in SunOS and 4.3BSD or am I missing something obvious? If this is
a problem, what is the fix?

Please respond to me via email as I rarely read this group!
Any help would be greatly appreciated!

I am enclosing a sample program.
----------------cut here---------------------------------------

#include <varargs.h>
#include <stdio.h>
main()
{
	static char ppp[] = "message";
	char *next = "error";
	foo(ppp); <---- calling foo with only  ppp as param
			prints "message error"
}

foo(va_alist)
va_dcl
{
	va_list ap;
	char * ptr;
	va_start(ap);

	while ((ptr = va_arg(ap, char *)) != NULL)
		printf("%s  ", ptr);
	va_end(ap);
	
	printf("\n");
}

------------------------cut here--------------------------------
--
Srinivas Madhur	
sm@gator.cacs.usl.edu
sm@cacs.usl.edu
.!dalsqnt!gator!sm