error linking to my own custom module

[Lars T. Kyllingstad]

torhu wrote:
> On 11.11.2009 04:57, Sean Fennell wrote:
>> I'm very green to D, just learning it now.
>> I have a module that I wrote.  Its pretty simple, just helper 
>> functions to get input from user as certain data types
>> GetInt()
>> GetString()
>> GetChar()
>> etc...
>>
>> I compiled the module using dmd -lib mymod.d which output mymod.a
>>
>> Now I've imported my module into ask.d to test it and I get the 
>> folliowing linking error when I try to compile:
>>
>> ask.o:(.data+0x4c): undefined reference to `_D4mymod12__ModuleInfoZ`
>> My dir structure looks like this:
>>
>> project/
>> ---ask.d
>> ---lib/
>> ------mymod.d
>> ------mymod.a
>>
>> and my import line is:
>>
>> import lib.mymod;
>>
>> Anyone seen this before? Using linux dmd v2.036
>>
>> Thanks!
>>
> 
> You have to hand all the files to the compiler, otherwise there will be 
> missing symbols when the compiler runs the linker.
> 
> Like this:
> dmd ask lib/mymod
> 
> Compiling to a library first, like you did, will work too.  But you have 
> to hand the compiler everything when you want to create the actual 
> executable:
> 
> dmd ask lib/mymod.a
> 
> There are build tools, like dsss, that will automate this for you.


I've found rdmd to be a very useful program. It will track down all 
imports in your program and feed the relevant files to the compiler. 
Here are some examples:

To compile and run your program:
   rdmd ask

To compile, but not run your program:
   rdmd --build-only ask

Actually, I tend to just put a shebang line in my main D source file and 
mark it as executable:

   ask.d:
      #!/path/to/rdmd --shebang
      import lib.mymod;
      ...

Then, after you make changes to your program and want to test it, you 
just run ./ask.d. :)

Note that rdmd only creates a temporary executable, so it's more of a 
testing tool than a build tool.

-Lars