How to use the -I command line switch?

[jmh530]

On Wednesday, 3 January 2018 at 17:10:22 UTC, tipdbmp wrote:
>> dmd main.d C:\libs\my_module.d
> That does not use the -I switch.
>
> It compiles if I specify the full path to my_module.d:
>     dmd -IC:\libs main.d C:\libs\my_module.d
>
> I don't understand the error message though.

I tried a few other options, but I don't use it enough to know 
the trick to get it working. I tend to use either dub, setting 
the path environmental variables, or the absolute path. Hopefully 
someone else can let you know. If it's a bug, it should be in 
bugzilla, but sometimes I just assume I screwed something up.