Re: aligned_alloc (C11) calls posix_memalign (posix) unconditionally: bug?

[Thomas Preudhomme <thomas dot preudhomme at foss dot arm dot com>]

On 27/09/16 13:29, Sebastian Huber wrote:
> Hello,

Hi Sebastian,

> On 23/09/16 18:55, Thomas Preudhomme wrote:
> > Hi there,
> >
> > GCC testcase g++.dg/cpp1z/aligned-new6.C fails to build on arm-none-eabi
> > because it pulls aligned_alloc which requires posix_memalign which is not
> > defined for arm-none-eabi targets.
> >
> > Is this a case where some code is simply missing to make this work on
> > bare-metal targets or is this a bug? I thought posix could only be expected
> > when targetting a system with OS and therefore posix_memalign should not be
> > called for bare-metal targets.
>
> do you want to support the C11 aligned_alloc() for arm-none-eabi targets?

Fair enough. Does newlib aim to have a good support of C11 though? If no one 
solution would be to teach GCC that C11 test should be skipped for newlib targets.

> If yes, then you need an implementation. If you don't want one based on
> posix_memalign(), then you have to tell this Newlib somehow.

I don't think there is any other choice at the moment. I did not find any 
conditional code in aligned_alloc.c and this file is also built unconditionally. 
So I think it's just a matter of doing the actual work if someone cares enough 
about this.

Thanks for your answer.

Best regards,

Thomas