[LTP] [PATCH 2/2] lib: build check parameters for tst_brk()

Petr Vorel
2018-12-05T09:25:21Z

Hi Li, Jan,

> > > Alternative would be link time failure, with a symbol name suggesting what went wrong.
> > Not sure, how exactly you want to do it, but seems to be more portable than
> > requiring specific gcc version (although 4.3 is very old and __attribute__
> > format is supported by clang as well).

> I took an rough look at the kernel method, maybe we can achieve that
> conditionally?

> --- a/include/tst_common.h
> +++ b/include/tst_common.h
> @@ -65,4 +65,23 @@
> ERET; \
> })

> +#define GCC_VERSION (__GNUC__ * 10000 \
> + + __GNUC_MINOR__ * 100 \
> + + __GNUC_PATCHLEVEL__)
> +
> +#if GCC_VERSION >= 40300
Didn't you mean reverse?
#if GCC_VERSION < 40300

But this idea does not work for clang, which always use same version:
__GNUC__: 4
__GNUC_MINOR__: 2
__GNUC_PATCHLEVEL__: 1
(tested on clang 3.9, 5.0, 6.0)

There should be also CLANG_VERSION
__clang_major__
__clang_minor__
__clang_patchlevel__

Not sure, which clang version is compiled, even clang 4.0 works well:
https://travis-ci.org/pevik/ltp/builds/463734307
Maybe we could afford to skip check (searching for __clang__).

> +# define BUILD_BUG_ON_MSG(cond, msg) \
> + compiletime_assert(!(cond), msg, tst_brk_detect_)
...

Kind regards,
Petr