int128 error

[Touros Spoon]

Jeffrey,

thanks for the quick response. I actually tried appending LL to the end of 
the value, but the compiler is still complaining, which isnt surprising 
because a test shows that long long has a sizeof of 8 bytes, whereas 
__int128_t reports 16 bytes.

btw Im compiling with -march=core2 and its a 64 bit cpu and linux distro.

Regards

TS

----- Original Message ----- 
From: "Jeffrey Walton" <noloader@gmail.com>
To: "Touros Spoon" <touros.spoon@gmail.com>
Cc: <gcc-help@gcc.gnu.org>
Sent: Sunday, January 02, 2011 6:34 PM
Subject: Re: int128 error


> wibble=170141183460469231731687303715884105727;
wibble=170141183460469231731687303715884105727LL;

or

wibble=170141183460469231731687303715884105727UL;

On Sun, Jan 2, 2011 at 11:24 AM, Touros Spoon <touros.spoon@gmail.com> 
wrote:
> I have been trying to use the gcc extension __int128, but although I am 
> able
> to declare a variable, when I test it by assigning a value, gcc warns me:
> "constant value is too large for its type".
>
> I am using gcc 4.4.4 on 64 bit Slackware 13.1 with a core 2 duo processor.
>
> This is the code Im using to test it:
>
>
> #include <iostream>
>
> int main ()
>
> {
>
> __int128_t wibble;
>
> wibble=170141183460469231731687303715884105727;
>
> std::cout << "size of wibble: " << sizeof(wibble) << std::endl;
>
> return 0;
>
> }
>
>
>
> Unless Im mistaken, the maximum value that a signed int128 should be able 
> to
> cope with is 170141183460469231731687303715884105727. However I tried
> knocking off a few digits to see what happened and the compiler is still
> complaining. The output of the above program displays a sizeof result of 
> 16
> for "wibble" indicating that it is seeing __int128_t as a 16 byte (128 
> bit)
> integer. So I guess the problem is with the assignment, perhaps something
> Ive missed?
>
> I put this on the gcc list because although it is probably a c++ problem,
> the only resources I can find relevant to this are related to external 
> math
> libraries.
> Has anyone else come accross this problem / can see what I have done wrong
> and if so, please can you advise.
>
> Regards
> TS
>