Incorrect va_list 'vl' used before va_start() was called.

[Nick Andrews]

We have the following code that is incorrectly flagged -:

void foo(int bar, va_list ap)
{
va_list ap2;
va_copy(ap2, ap);
// Do something here with ap2...
va_end(ap2);
}

It reports ap2 is used at va_end(ap2) before va_start(), however va_start
is not necessary with va_copy because it explicitly initialises the va_list
(and is documented to do so..)

[CHR]

I can't reproduce this in either C or C++ mode with v2.3.

[Coldfirex]

We see this in v2.5.
Here is a one example

[xiang xia]

Hi, I came across this problem too. I'm using cppcheck 2.6 built on Mac. Maybe it is a false positive??

[CHR]

Here's a reduced example from @coldfirex's post:

#if __GNUC__ < 4
#define va_copy     __va_copy
#endif

void SetTo(va_list _list)
{
    va_list list;
    va_copy(list, _list);
    va_end(list);
}

The error depends on __GNUC__, which is not part of gnu.cfg. One workaround is to run cppcheck with -D__GNUC__=4.
@agassy: Is your code similar to this?

[xiang xia]

Thank you for reply. My code is similar to your example while I'm using cppcheck in visual studio. In <stdargs.h> from MSVC include files, the macro definitions are as below. Any remedies I can use here?</stdargs.h>

#pragma once
#define _INC_STDARG

#include <vcruntime.h>

_CRT_BEGIN_C_HEADER

#define va_start __crt_va_start
#define va_arg   __crt_va_arg
#define va_end   __crt_va_end
#define va_copy(destination, source) ((destination) = (source))



_CRT_END_C_HEADER

[xiang xia]

Well, I fixed this problem by using "-Uva_copy". Not so graceful, though.
I just wonder when I specify my project using "--project" option, how can I configure to skip the system include files and using the *.cfg libs？