gtkd.lib: Error 43: Not a Valid Library File

[Mike Parker via Digitalmars-d-learn]

On Tuesday, 26 January 2016 at 22:30:24 UTC, Enjoys Math wrote:
> On Tuesday, 26 January 2016 at 22:10:42 UTC, Enjoys Math wrote:
>> I get this message either compiling at command line -or- in 
>> VisualD.
>>
>> At command line when I add -m64, I get another error:
>>
>>
>> C:\MyProjects\___LIGHTSHOWAPP\___LIGHTSHOWAPP>dmd -m64 main.d 
>> -L+gtkd
>> LINK : fatal error LNK1181: cannot open input file '+gtkd.obj'
>> --- errorlevel 1181
>
> Got it to compile and run at command line!
>
> The proper command line is:
> dmd main.d -m64 -Lgtkd.lib
>
> (without +, with .lib)

You appear to have a lack of understanding of linker options. If 
I'm wrong, just ignore the rest of this post.

-L tells DMD to pass an argument to the linker. Each linker it 
uses accepts options in a different format. The + you used above 
has no connection library files on any linker. It's used by 
OPTLINK, the default linker DMD uses, to set a path on which to 
search for libraries. So, if you had all of your libraries in 
C:\mylibs, then you could pass this to dmd:

dmd -L+C:\mylibs main.d -Lgtkd.lib

After compiling main.d, DMD will call optlink with +C\mylibs and, 
assuming gtkd.lib is in that directory, optlink will find it. 
When you use -m64 (or -m32mscoff), DMD is using the Microsoft 
Linker. It will not recognize the +, as it has a different syntax 
for specifying the path.

dmd -L/LIBPATH:C:\mylibs main.d -Lgtkd.lib

In both cases, you can actually drop the -L when specifying the 
libraries:

dmd -L+C:\mylibs main.d gtkd.lib
dmd -L/LIBPATH:C:\mylibs main.d gtkd.lib

Here, dmd will recognize the .lib extension and will pass the 
library names to the linker without the need for -L.

When compiling on other platforms where DMD uses the GNU (or 
compatible) linker, it would look like this:

dmd -L-L/path/to/mylibs -L-lgtkd

This linker accepts -L as the switch to specify the path, so -L-L 
tells DMD to send that on. It also requires -l (lowercase l) to 
specify libraries, so -L-l will do that. The linker will actually 
convert the 'gtkd' string to libgtkd.a or libgtkd.so. I can't 
recall if passing either, with the extension, on the command line 
without -L-l (e.g. libgtkd.a or libgtkd.so) works or not.