This is the mail archive of the
mailing list for the GDB project.
Re: GDB AIX build broken
On 10/25/2016 01:51 AM, David Edelsohn wrote:
> On Mon, Oct 24, 2016 at 8:31 PM, Pedro Alves <firstname.lastname@example.org> wrote:
>> On 10/25/2016 01:13 AM, David Edelsohn wrote:
>>> On Mon, Oct 24, 2016 at 7:00 PM, Pedro Alves <email@example.com> wrote:
>>>> That's a hint, but it can't be the fix. common-defs.h must be the
>>>> first file included. I suspect that gnulib's inttypes.h
>>>> replacement logic is broken on AIX.
>>> The gnulib import definitely is the commit that caused the breakage.
> gnulib weaves between its header files and the system header files in
> dangerous ways. It incorrectly assumes that it's version of a header
> file always will be seen before a system header file. But a system
> header file may include another system header file directly.
Sure, and if so, gnulib will be patched to handle it somehow.
> AIX inttypes.h protects the printf format macros with
> #if !defined(__cplusplus) || defined(__STDC_FORMAT_MACROS)
There you go. See my other email. This means AIX's
headers haven't been updated for C++11 yet. C++11 overruled
C99's decision to require the __STDC_FORMAT_MACROS input macro,
and the C11 followed suit.
> gnulib inttypes.h helpfully provides
> /* Some pre-C++11 <stdint.h> implementations need this. */
> # if defined __cplusplus && ! defined __STDC_FORMAT_MACROS
> # define __STDC_FORMAT_MACROS 1
> # endif
> # include_next <inttypes.h>
> # endif
Right, that old way of defining __STDC_FORMAT_MACROS isn't complete.
That's why I wrote the fix at:
That now defines __STDC_FORMAT_MACROS in config.h instead. Now the
problem is that gnulib's configure runs with a C compiler,
not a C++ compiler, so my fix doesn't really make a difference. I had
written that assuming we'd change to configure/build gnulib
with a C++ compiler, back then.
So the fix is to do what I had suggested here
If this causes a problem
somewhere, we can re-define the macros higher up in the file, before
system headers are included.
> Should __STDC_FORMAT_MACROS be defined in gdb/common/common-defs.h and
> gdb/defs.h (if btrace.c also is changed)?
Exactly, almost. Only common/common-defs.h should be changed.
defs.h includes common/common-defs.h first thing,
before system headers. ("common" refers to the file being
shared between gdb and gdbserver.)