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Re: [Qemu-devel] [libfdt][PATCH v3] implement strnlen for systems that n
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [libfdt][PATCH v3] implement strnlen for systems that need it |
Date: |
Tue, 24 Oct 2017 14:18:22 +0200 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
On Mon, Oct 23, 2017 at 05:27:26PM +0100, Peter Maydell wrote:
> On 23 October 2017 at 17:09, Stefan Hajnoczi <address@hidden> wrote:
> >> +/* strnlen() is not available on Mac OS < 10.7 */
> >> +# if (MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7)
> >
> > Does this cover the case where MAC_OS_X_VERSION_MAX_ALLOWED is set to
> > <1070 on a 10.7+ build machine? It's possible that the <string.h>
> > header would define strnlen() and your code redefines the function
> > (compiler error).
>
> In that case you don't want to use the strnlen() declaration
> from the header, you want the inline somehow, because even if
> the declaration is present and using it doesn't fail compile
> the definition won't be around at runtime.
Perhaps one way around this case is to:
# if !defined(MAC_OS_X_VERSION_10_7) || (MAC_OS_X_VERSION_MAX_ALLOWED <
MAC_OS_X_VERSION_10_7)
# include <string.h> /* make sure it isn't included again */
# define strnlen fdt_strnlen
static inline fdt_strnlen(...) { ... }
This way the symbol strnlen() isn't used and the system headers cannot
cause problems.
Stefan