public class OpenCLKernel(size_t dim = 1) if( (dim >= 1) && (dim <= 3) )
{
	public this( OpenCLProgram program, in string kernelName )
	{
		// ...
	}
}

I have a class definition as above. When I want to create an instance as below,

OpenCLKernel k = new OpenCLKernel( program, "kernelName" );

compiler tells me,

/test2.d(168): Error: template class `OpenCLKernel(ulong dim = 1) if (dim >= 1 && (dim <= 3))` is used as a type without instantiation; to instantiate it use `OpenCLKernel!(arguments)`

The "dim" template parameter has a default value of 1 already. Why does it still force me to give a value?

(DMD64 D Compiler v2.096.0)

On Sunday, 9 May 2021 at 10:53:49 UTC, tcak wrote:

It doesn't, but it does require you to instantiate the template. You can do OpenClKernel!() to use the default value.

But without that ! instantation, you're just referring to a template name, not a class.

You might want to try something like

class GenericOpenClKernel(....) {}

alias OpenClKernel = GenericOpenClKernel!();

depending on the intended uses.