> On Tuesday, 9 October 2018, 16:16:44 BST, wolfgang.ma...@kabelmail.de
<wolfgang.ma...@kabelmail.de> wrote: > Is this a Bug?
> cellRendererText.text = ("%"+int64.FORMAT).printf((int64)obj); <<----
> int64.FORMAT = "li"
> this works, but when i try this, witch is the same
> cellRendererText.text = ("%li").printf((int64)obj);
> i get thiss error
> application.vala:192.45-192.54: error: Argument 1: Cannot convert from
> `int64' to `long'
I think it should be %lli. Try:
void main () {
int64 a = 1234567890123456789LL;
print ("%li\n".printf ((int32)a));
print ("%lli\n".printf (a));
}
A 'long' is at least 32 bits, a 'long long' is at least 64 bits. A good summary
is https://en.wikipedia.org/wiki/C_data_types
I think that was the conclusion I came to when I wrote that up in the Genie
docs: https://wiki.gnome.org/Projects/Genie#Numbers
int64.FORMAT in Vala is bound to GLib's G_GINT64_FORMAT. See the Vala binding:
https://gitlab.gnome.org/GNOME/vala/blob/master/vapi/glib-2.0.vapi#L687
The GLib documentation advises 'This is the platform dependent conversion
specifier for scanningand printing values of type gint64' See
https://developer.gnome.org/glib/2.56/glib-Basic-Types.html#G-GINT64-FORMAT:CAPS
To my mind that is wrong in GLib. Now there may be some platform reason for
doing this, but I suggest you raise an issue with GLib at
https://gitlab.gnome.org/GNOME/vala/issues then we can take it from there.
Note how the use of just %li in my code example truncates the number. The Vala
compiler is recognising this in your second example and giving an error. If you
cast to int32 it should compile. The Vala compiler has not been set up to
recognise the creation of %li using string concatenation. So it is passed
through to the output C and the C compiler does its thing with a resulting
potential loss of data. Is this a bug in the Vala compiler? May be, but there
may also be a limit to how much checking can be coded in to the compiler. Of
course if someone submitted a patch that made it just work then that would be a
different story :) BTW to read the generated C code use the --ccode switch with
valac.
Hope that helps,
Al
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