>Number:         598
>Category:       lib
>Synopsis:       stdarg.h incorrectly handles padding.
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    gnats-admin (Library Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Nov 29 14:35:04 1994
>Originator:     Christian E. Hopps
>Organization:
"	"
>Release:        1.0
>Environment:
	NetBSD sun-lamp.cs.berkeley.edu 1.0 NetBSD 1.0 (SUN_LAMP) (i386)
	NetBSD water.emich.edu 1.0 NetBSD 1.0 (WATER) (m68k/amiga)

>Description:
	Stdarg.h mishandles odd aligned structs passed by value.
>How-To-Repeat:

	#include <assert.h>
	#include <stdio.h>
	#include <stdarg.h>


	typedef struct {
		char c;
	} Cstruct;

	static int tryit(const char *fmt, ...)
	{
		int ctr = 0;
		va_list ap;

		va_start(ap, fmt);
		for (; *fmt; ++fmt)
			switch (*fmt) {
			case 'i':
				assert(va_arg(ap, int) == ++ctr);
				break;
			case 'd':
				assert(va_arg(ap, double) == ++ctr);
				break;
			case 'p':
				assert(va_arg(ap, char *)[0] == ++ctr);
				break;
			case 's':
				assert(va_arg(ap, Cstruct).c == ++ctr);
				break;
			}
		va_end(ap);
		return (ctr);
	}

	int main()
	{
		Cstruct x = {3};

		assert(tryit("iisdi", '\1', 2, x, 4.0, 5) == 5);
		assert(tryit("") == 0);
		assert(tryit("pdp", "\1", 2.0, "\3") == 3);
		printf("sizeof(va_list) == %u\n", sizeof(va_list));
		puts("SUCCESS testing <stdarg.h>");
		return (0);
	}
>Fix:
	Eventually.
>Audit-Trail:
>Unformatted: