Re: Can't use long long variables?

[Alexander Malmberg]

Adam Fedor wrote:
> > Is there any way to include this setting into make? Up to now I always
> > took it for granted that my Suse Linux didn't have long long support
> > and never thought about it.
> 
> I don't know why it isn't automatically defined. From what I've read
> via google, if you need it, you should just define it.  Although I
> think we might have to think a little about the implications of
> defining it everywhere. I'd prefer just to define it where it is
> needed.

Agreed. If it was perfectly safe, it would probably be on by default
already.

FWIW, David Ayers and I investigated this yesterday, and the situation
seems to be:

c99 defines LLONG_MAX.

Recent versions (>=3.0.4, it seems) will define LLONG_MAX, but only if
you give it the -std=c99 option. No released version of gcc defaults to
c99 mode, although the manual claims that they will, eventually.

Some older versions of gcc define LONG_LONG_MAX. Not really sure which;
3.0.1 does, 2.95.2 doesn't.

Old versions of glibc (at least 2.0.7) define LONG_LONG_MAX always.

Newer versions of glibc (at least 2.2.5) define LONG_LONG_MAX only if
_GNU_SOURCE is defined.


(Of course, both -std=c99 and _GNU_SOURCE affect lots of things in
addition to these defines.)

- Alexander Malmberg