Re: [Vala] Int64 operations, I'm confused

[pancake <pancake youterm com>]

Nope, it is not strange, it is what it should be.

%lld is not valid on windows, so it is taken as %d. so if you dont use 
the right format windows will execute this:

>      stdout.printf ("val6: %d, val7 : %d\n", val6, val7);

instead of

>      stdout.printf ("val6: %lld, val7 : %d\n", val6, val7);

What happens here is that %d will get the first 4 bytes of val6 and the 
second %d will get the next 4 bytes of val6. Resulting in 96 and 0. 
(little endian matters here).

So again, please use the correct, portable format strings. %lld is not 
portable. It will work on all known unixes, but fail on windows because 
they use %I64d.

On 07/31/13 10:54, raum no-log org wrote:
> Ok, the value stored in int type variable is correct (I mean 12) but try
> the following code :
>
> void main() {
>      int64 val6 = 96;
>      int val7 = (int) (val6 / 8);
>      stdout.printf ("val6: %lld, val7 : %d\n", val6, val7);
>      stdout.printf ("%d\n", val7);
> }
>
> output :
> $ a
> val6: 96, val7 : 0
> 12
>
> Int64 is correctly disdplayed with "%lld" format, int is not correctly
> displayed at first.
>
> Strange ? isn'it ? :)
>
> But ok, I've got the right value.
>
>
> generated C code :
> /* a.c generated by valac 0.20.1, the Vala compiler
>   * generated from a.vala, do not modify */
>
> #include <glib.h>
> #include <glib-object.h>
> #include <stdio.h>
>
>
>
>
> void _vala_main (void);
>
>
> void _vala_main (void) {
>         gint64 val6;
>         gint val7;
>         FILE* _tmp0_;
>         FILE* _tmp1_;
>         val6 = (gint64) 96;
>         val7 = (gint) (val6 / 8);
>         _tmp0_ = stdout;
>         fprintf (_tmp0_, "val6: %lld, val7 : %d\n", val6, val7);
>         _tmp1_ = stdout;
>         fprintf (_tmp1_, "this is correct : %d\n", val7);
> }
>
>
> int main (int argc, char ** argv) {
>         g_type_init ();
>         _vala_main ();
>         return 0;
> }
>
>
>
>
>
>
> > not for me
> >
> > On 07/31/13 10:27, raum no-log org wrote:
> > >       int64 val6 = 96;
> > >         int val7 = (int) (val6 / 8);
> >
> > $ cat a.vala
> > void main() {
> >           int64 val6 = 96;
> >           int val7 = (int) (val6 / 8);
> >           stdout.printf ("%d\n", val7);
> > }
> > $ vala a.vala
> > 12
> >
> > If you use the wrong format string you are going to display wrong data.
> >
> > This is, windows is 32bit, and values are pushed on the stack from 4
> > bytes to 4, if the printf format expects a 64bit value it will fetch 4
> > bytes from the value and 4 bytes more from the stack (which can be zero
> > or any other value) causing the output you see.
> >
> > Please, use the proper format string.
> >
> > You can see the C code to verify if the compiler does it right, but you
> > didnt provided the valac version and I doubt vala can do such a simple
> > operation wrong.
> >
> > --pancake