Linking C libraries with DMD

[jmh530 via Digitalmars-d-learn]

I'm trying to understand calling C libraries from D on Windows 
with DMD. I made a simple example and compiled it with a static 
library fine (so I've converted the .h file correctly). Then, I 
compiled with gcc to a shared library (because I cannot for the 
life of me figure out how to do this with DMC). I then used 
implib to generate a .lib file (the fact that this is necessary 
is not described nearly well enough in the documentation).

The next step is getting this to compile with dmd. I'm getting an 
error that the function isn't getting called, which is suggesting 
that I'm not linking the .lib file with DMD properly.

The dmd page
https://dlang.org/dmd-windows.html
explains that -L is used to pass stuff to the linker. It seems to 
indicate that this should be the folder that the library is in. 
The dll and lib files are in the same folder as the .d file I'm 
trying to compile. So presumably, this should be -L. or -L\. or 
like -LC:\folder\. But nothing like that works. There's a link on 
the dmd page to optlink, which doesn't really help me figure this 
out either. There's also some stuff about set LIB in the sci.ini. 
Not sure I'm supposed to mess with that.

The LearningD book has some examples as well. I don't have it in 
front of me right now, but I think I tried what they recommend 
also. Nevertheless, I feel like the documentation should be clear 
enough so that this isn't so frustrating.