Re: print 64bit-integer

Chris McDonald said:

Richard Heathfield <rjh@xxxxxxxxxxxxxxx> writes:

I'm not convinced about the "portable"! :-) Nor am I convinced of
the existence of a PRId64 modifier, but this may simply be because
I have paid little attention to C99. I have taken a brief look at
what the Standard has to say on the matter, but alas, I remain
unconvinced. Can you convince me that PRId64 (a) exists at all,
and (b) is /required/ to exist?


An *existence* proof is that it exists in gcc 3.2.2 (and probably
beyond),
certainly in gcc 4.0.1 on OS-X (you may choose to just believe me
on that).

Um, sorry. I meant an existence proof based on the Standard - i.e. a
demonstration that the Standard specifically caters for an
implementation creating such a macro (along the same lines as the
Standard catering for an implementation providing uint24_t without
requiring it to do so). Having said that, however, see below!

I believe that this makes it widely, though not universally,
portable.

No, I can't interpret Sect 7.8.1 to read that it /must/ exist.

Neither can I. (So much for "portable".) But re-reading that section
more carefully, I belatedly realise that the Standard does say that
N is to be replaced by a type width, so yes, at least I can now
agree that PRId64 /can/ exist.

For maximum portability, however, it should be avoided.

--
Richard Heathfield <http://www.cpax.org.uk>
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999
.

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