C API / const char *text / std.string.toStringz pointer is always NULL on C side

Robert M. Münch robert.muench at saphirion.com
Wed May 16 16:53:27 UTC 2018

On 2018-05-16 15:09:41 +0000, rikki cattermole said:

> On 17/05/2018 3:07 AM, Robert M. Münch wrote:
>> I have an extern(C) function in a DLL with this signature:
>> result* myfunc(double x, double y, const char *text, stuff *myStuff, 
>> bool flag);
>> I call it like this:
>> result = myfunc(0, 0, std.string.toStringz("1"), stuff, true);
>> The problem is, that on the DLL side *text is always NULL. I doesn't 
>> matter what I put as third argument. And even more strange, I have an 
>> other function with a const char* as first argument. There everything 
>> is working...
>> Any idea what cause this could be? This is really strange...
> Please post the C function prototype.

Well, for C see above on the D side:

	extern(C) {
   		result myfunc(double x, double y, const char *text, stuff 
*myStuff, bool measureOnly);

result is a:

    extern (C++, class) struct result {
      double w;
      double h;

Robert M. Münch
smarter | better | faster

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