Re: [PATCH v1 1/1] selftests/sgx: Fix the implicit declaration of asprintf() compiler error

["Jarkko Sakkinen" <jarkko@kernel.org>]

On Sat May 11, 2024 at 12:02 AM EEST, Mirsad Todorovac wrote:
> On 5/10/24 22:52, John Hubbard wrote:
> > On 5/10/24 1:37 PM, Mirsad Todorovac wrote:
> > ...
> >> The fix defines __USE_GNU before including <stdio.h> in case it isn't already
> >> defined. After this intervention the module compiles OK.
> > 
> > Instead of interventions, I believe the standard way to do this is to simply
> > define _GNU_SOURCE before including the header file(s). For example, the
> > following also fixes the compilation failure on Ubuntu:
> > 
> > diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
> > index 9820b3809c69..bb6e795d06e2 100644
> > --- a/tools/testing/selftests/sgx/main.c
> > +++ b/tools/testing/selftests/sgx/main.c
> > @@ -1,6 +1,7 @@
> >  // SPDX-License-Identifier: GPL-2.0
> >  /*  Copyright(c) 2016-20 Intel Corporation. */
> >  
> > +#define _GNU_SOURCE
> >  #include <cpuid.h>
> >  #include <elf.h>
> >  #include <errno.h>
> > 
> > 
> > However, that's not required, because Edward Liaw is already on v4 of
> > a patchset[1] that fixes up the _GNU_SOURCE problem for all selftests.
> > 
> > [1] https://lore.kernel.org/all/20240510000842.410729-2-edliaw@google.com/
> > 
> > thanks,
>
> Hi,
>
> Yes, I actually like Ed's solution more, because it solves the asprintf() prototype
> problem with TEST_HARNESS_MAIN macro for all of the tests.
>
> Sorry for the noise and the time wasted reviewing. 8-|
>
> Best regards,
> Mirsad Todorovac

Yeah, well, it does not cause any harm and I was not sure when the patch
set is in mainline so thus gave the pointers. Anyway, never ever touch
__USE_GNU and always look at the man page from man7.org next time and
should cause less friction...

BR, Jarkko