D for sciencetific scripting / rapid protoryping

[Mike Parker]

On Tuesday, 22 October 2019 at 07:40:01 UTC, Prokop Hapala wrote:

>
> 1) I'm not speaking about OpenGL and SDL specifically (that was 
> just small example which I tried first)

FYI, the BindBC bindings can be configured as dynamic (in which 
all the of C library functions are declared as function pointers 
and the C shared library must be loaded manually at runtime) or 
static (in which the C library functions become normal function 
declarations with no implementation and there is a link-time 
dependency on the C static or shared library). The exception is 
OpenGL, for which there is no static binding.

The dynamic bindings add the overhead of the function pointer 
declarations when linked. It's insignificant for most of them. 
The biggest bindbc-opengl, depending on how many extensions you 
configure (it's extremely high for DerelictGL3 most of the time, 
as it tends to pull in more extensions).

>
> 2) I'm more concerned about how to D compiler links 
> dependencies when it compiles simple .d program (with lot of 
> dependencies).

When using dub, it depends on the package configuration of each 
dependency. All of the Derelict and BindBC packages, for example, 
are configured to build as static libraries. It didn't (and 
doesn't) make sense to me to compile a binding as a shared 
library. Dub packages can also be configured as shared libraries, 
or simply as "library" (I haven't investigated what that means). 
Some might provide custom subconfigurations to choose static or 
shared.

The biggest overhead with DMD output tends to come from the 
standard library. On Windows, the static library the only option. 
IIRC on Linux it's necessary to pass -defaultlib=libphobos2.so to 
DMD to link the shared lib. I don't know how LDC handles it.