Problem Passing Struct to C

[Jacob Carlborg]

On 2011-05-06 15:23, Steven Schveighoffer wrote:
> On Fri, 06 May 2011 09:16:02 -0400, Jacob Carlborg <doob at me.com> wrote:
>
>> On 2011-05-06 11:56, Mike Parker wrote:
>>> Testing out a new binding I knocked up for a C library. One of the
>>> functions takes a struct by value. It looks somewhat like this:
>>>
>>> struct S {}
>>> struct Color
>>> {
>>> float r,g,b,a;
>>> }
>>>
>>> extern C void function(S* s, Color color, int x, int y, in char*)
>>> draw_text;
>>>
>>> Now, there is another function that adjusts color values when making a
>>> color. In C, it is sometimes used like so:
>>>
>>> draw_text(s, map_color(255, 0, 0, 0), 0, 0, "Blarg");
>>>
>>> When I'm calling draw_text like this on the D side, my text output is
>>> corrupt. I keep getting weird things like ^^P^, but in the appropriate
>>> color. It's consistent, no matter what string I pass, but is different
>>> for each color value. If I call draw_text like this:
>>>
>>> auto color = map_color(...);
>>> draw_text(s, color, 0, 0, "Blarg");
>>>
>>> It works as expected. Has anyone else seen this, or know of a
>>> workaround? I'm going to dig through bugzilla later on and see if it's
>>> been reported already, but I'm curious if anyone knows of the cause off
>>> hand.
>>
>> You need to convert the string into a C string;
>>
>> import std.string;
>> auto color = map_color(...);
>> draw_text(s, color, 0, 0, "Blarg".toStringz);
>>
>
> No, D implicitly casts string literals to zero-terminated const(char)*.
> That part is fine.
>
> -Steve

Since when?

-- 
/Jacob Carlborg