• Walter Gray (22/22) Apr 23 2014 Hi there,
• Steven Schveighoffer (10/30) Apr 23 2014 Every module in D generates a moduleinfo object. The runtime links all
• bearophile (6/9) Apr 23 2014 I don't understand why that's not regarded as a job for the

"Walter Gray" <walter.r.gray gmail.com> writes:

Hi there,
  I'm currently trying to set up a small demo project using the 
Leap Motion API in D.  I've run SWIG with -d -d2, and created the 
intermediate C++ DLL along with a pair of .d files, leap.d and 
leap_im.d.  I'm new to D, but very interested and I'd like to set 
this up in an idiomatic way & be able to share it, but I'm 
running into a problem: When I create a simple sample project 
with Visual D and import the Leap module, I get a number of 
linker errors:

Error 42: Symbol Undefined 
_D4Leap10Controller6__ctorMFZC4Leap10Controller (Leap.Controller 
Leap.Controller.__ctor())
Error 42: Symbol Undefined _D4Leap10Controller7__ClassZ
Error 42: Symbol Undefined _D4Leap12__ModuleInfoZ

I've discovered that if I run dmd manually and link in the object 
files for leap.d and leap_im.d, these problems go away, and if I 
create a separate project to build a .lib and then link to that 
it also solves the issue.  Both of these options seem hacky to me 
though, and I'm wondering if there's some 3rd option I'm missing 
- the files contain the entire definitions, so why would it be 
necessary to link to them AND specify them as imports?  What am I 
missing here?

"Steven Schveighoffer" <schveiguy yahoo.com> writes:

On Wed, 23 Apr 2014 20:34:11 -0400, Walter Gray <walter.r.gray gmail.com>  
wrote:

 Hi there,
   I'm currently trying to set up a small demo project using the Leap  
 Motion API in D.  I've run SWIG with -d -d2, and created the  
 intermediate C++ DLL along with a pair of .d files, leap.d and  
 leap_im.d.  I'm new to D, but very interested and I'd like to set this  
 up in an idiomatic way & be able to share it, but I'm running into a  
 problem: When I create a simple sample project with Visual D and import  
 the Leap module, I get a number of linker errors:

 Error 42: Symbol Undefined  
 _D4Leap10Controller6__ctorMFZC4Leap10Controller (Leap.Controller  
 Leap.Controller.__ctor())
 Error 42: Symbol Undefined _D4Leap10Controller7__ClassZ
 Error 42: Symbol Undefined _D4Leap12__ModuleInfoZ

 I've discovered that if I run dmd manually and link in the object files  
 for leap.d and leap_im.d, these problems go away, and if I create a  
 separate project to build a .lib and then link to that it also solves  
 the issue.  Both of these options seem hacky to me though, and I'm  
 wondering if there's some 3rd option I'm missing - the files contain the  
 entire definitions, so why would it be necessary to link to them AND  
 specify them as imports?  What am I missing here?

Every module in D generates a moduleinfo object. The runtime links all  
these together and uses it to run static constructors and destructors. It  
also contains runtime type info for any items defined within the module.

Even if a module has only templates, or even if it's empty! You still have  
to compile and include it in the link step if it's imported from a module  
you are compiling.

As for Visual D, I don't know much about how it works.

-Steve

"bearophile" <bearophileHUGS lycos.com> writes:

Walter Gray:

 the files contain the entire definitions, so why would it be
 necessary to link to them AND specify them as imports?
 What am I missing here?

I don't understand why that's not regarded as a job for the 
compiler. But in the standard D distribution there are programs 
like rdmd that offer that functionality.

Bye,
bearophile