Bill Allombert on Tue, 15 Oct 2002 20:40:31 +0200

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Re: functions returning int with 'l' protocodes.

On Tue, 10 Sep 2002, Bill Allombert wrote:
> Comparison functions usually return an `int' not a `long'.
> This is correct since they always returns 0, 1 or -1.
> However some of them are available from GP, but there is
> not protoype letter for int, so we use l instead.
> But this is wrong, since on 64bit mechines, int is 32 bit and
> long 64bit.
> On ia64 PARI compiled with gcc -g (for all versions) do not pass
> the bench, because in some cases, (int) -1 became (long) 2^32-1,
> which is correct, since we have hid the cast from the compiler.
> FIx involves either add a new letter code for integers, or
> `upgrade' all functions return int to long.
> The second option seems better.

So Karim, what do you prefer ?

For the stable version: the only way we can keep the ABI safe is
to add a new array with the information about the output type
(long or int) and to cast correctly when needed.
Unfortunately this may slow GP down and is a bit ugly.
Also this will be an addendum to the API, but we already done it
by adding the PARI_VERSION definition, but this is not as bad,
since precisely the PARI_VERSION will allows programs to
know at compile time if the new array is there.