[cfarm-users] AIX portability

[Kaz Kylheku]

On 2022-09-21 01:32, Bruno Haible wrote:
> Kaz Kylheku wrote:
>> gcc -E - -D_XOPEN_SOURCE=500
> 
> Defining _XOPEN_SOURCE — or worse, _POSIX_SOURCE — on arbitrary platforms
> is a recipe for producing compilation errors.
> 
> On HP-UX/hppa, -D_XOPEN_SOURCE=500 is useful.
> On HP-UX/ia64, -D_XOPEN_SOURCE=600 is useful, but only in combination with
> -D_HPUX_SOURCE.
> On Solaris 11, -D_XOPEN_SOURCE=700 is useful.

I'm actually using 700; the problem reproduced with that value too, then
I searched for the smallest value which still reproduces the problem.

The 2018 edition of POSIX defines _XOPEN_SOURCE as the way to reveal XSI material:

  The _XOPEN_SOURCE Feature Test Macro

  [XSI] [Option Start] An XSI-conforming application shall ensure that
  the feature test macro _XOPEN_SOURCE is defined with the value 700
  before inclusion of any header. This is needed to enable the functionality
  described in The _POSIX_C_SOURCE Feature Test Macro and to ensure that
  the XSI option is enabled.

So this is a standard thing everyone must implement; the application could
never be wrong if it defines this.

I'm aware of platforms where it fails to reveal definitions.

But revealing broken definitions is something else.