What's up with GDC?

[Mike Parker via Digitalmars-d-learn]

On Saturday, 11 June 2016 at 06:22:27 UTC, Joerg Joergonson wrote:
>>
>> OpenGL32.lib and glu32.lib are part of the Windows SDK. 
>> Assuming you've got VS 2015 installed, they should be part of 
>> the installation and should be available out of the box. 
>> Adam's lib is solely for use with OPTLINK when compiling with 
>> DMD using the default -m32 on Windows, since DMD does not ship 
>> with the opengl lib. When compiling with -m32mscoff or -m64, 
>> it will use Visual Studios libraries.
>
> That's not true unless I'm not suppose to import them directly. 
> When I switch to 64-bit build I get same errors. Basically only 
> dmd x86 works.

It's true if everything is configured properly.


>
> 1. How to tell the difference between different libs and what 
> kind of libs are required for what kind of compiler and build.
>
>       x86    x64
> DMD    .      .
> LDC    .      .
> GDC    .      .
>
> Please fill in the table for windows, linux, etc.

On Windows/Mac/FreeBSD, if you know how to configure libraries 
for gcc, then you know how to configure them with DMD. You 
install the packages you need from your package manager, they are 
installed by default in the appropriate system paths, and when 
DMD invokes the system linker they will be found.

Windows is only problematic because there's no such thing as a 
system linker, nor are there any standard system paths for 
libraries. Given the following command line:

dmd foo.d user32.lib

The compiler will invoke OPTLINK, which it ships with. This 
guarantees that you always have a linker if DMD is installed. You 
will find several Win32 libraries in the dmd2/windows/lib 
directory. They are all a in OMF format for OPTLINK and they are 
all a bit outdated. With the above command line, the user32.lib 
in that directory will be used. If you need a Win32 system 
library that does not ship with DMD (such as OpenGL32.lib) you 
will need to provide it yourself in the OMF format to use it with 
OPTLINK.

Add either the -m32mscoff or -m64 command line switch and DMD 
will invoke whichever Microsoft linker it is configured to call, 
meaning it will no longer use the libraries that ship with DMD. 
If you've installed one of paid versions of VS, or one of the 
Community Editions, all of the Win32 libraries will be installed 
as well. If you're using one of the VS Express versions, you'll 
need a Windows SDK installed to have the Win32 libraries.
>
>
> 2. How does the D build system fetch the libs? It uses the 
> sci.ini path? What about Visual D?

Yes, on Windows, sc.ini is where the library paths are 
configured. If you installed DMD manually, or used the installer 
but installed Visual Studio after, then you will need to edit 
sc.ini to make sure the paths point to the proper VS locations. 
If run the DMD installer *after* installing Visual Studio, the 
installer will configure sc.ini for you. I recommend you take 
that approach. It just works.

On other systems, dmd.conf is used to configure the location of 
libphobos2, but system libraries are on the system path (just as 
when using gcc).

>
> Where does D look for these? I assume in the "libs" directory?
>    pragma(lib, "opengl32");
>    pragma(lib, "glu32");
>

On Windows, it looks on the path configured in sc.ini or whatever 
import path you have provided on the command line with -I, just 
as it does with any libraries you pass on the command line. So 
that means that compiling without -m32mscoff or -m64, it looks 
win the dmd2/windows/lib directory. Since opengl32 and glu32 do 
not ship with DMD, it will not find them there. So you either 
need to put COFF format libs there or tell the compiler where to 
find them with -I. With -m32mscoff or -m64, it looks for the 
Microsoft version of those libraries in the Visual Studio or 
Windows SDK installation, which you should have configured in 
sc.ini as I explained above.

On other systems, the OpenGL libraries are found on the system 
library path.

> 3. How to get different compilers and versions to play along? I 
> would eventually like to build for win/lin/osx for both x64 and 
> x86.

On Windows, Just make sure you provide any third-party libraries 
you need, along with any system libraries you need that DMD does 
not ship with, in the OMF format when using OPTLINK on Windows 
and tell DMD where to find them. When using the MS toolchain, the 
system libraries are all there, so you need not provide any. 
You'll just need to make sure any third-party libraries are in 
the COFF format (preferably compiled with the same version of 
Visual Studio you are using to link your D programs).

On Linuux and OSX, just make sure the dev packages of any 
libraries you need are installed. You do need to account for 
different libray names (e.g. Openg32.lib on Windows vs. libopengl 
elswhere, so your pragmas above should include '32' in the name 
only on Windows).

Alternatively, you might try one of the dynamic bindings[1] to a 
library you need, such as DerelictGL3. Then there is no link time 
dependency, as the shared libraries are loaded at runtime. On 
Windows, that completely eliminates the COFF vs. OMF issues. As 
long as the DLLs match your executable's architecture (32-bit vs. 
64-bit), then it doesn't matter what compiler was used to create 
them when loading them at runtime.
>
>
> I am using Visual D, BTW. It seems to have a lot of stuff setup 
> by default but I haven't went in and messed with the settings 
> much.

Well, when it invokes DMD, the compiler uses whatever you've 
configured in sc.ini for the system libraries. Anything else you 
can configure in Visual D's project settings.