I hope this is trivial, but I haven't been able to figure out how I'm supposed to pass an array of strings to C.  I thought I had it solved, as everything looks right when I test the parameters, but at run time, well....
Here's my most recent trial (out of several):

The D routine:

import   std.conv;
import   std.cstream;
import   std.stdio;
import   std.stream;
import   std.string;

extern (C)  int   cGtkInit(int, char**);

class DTK
{  private  static   bool  _initialized   =  false;
   this()
   {  int   i  =  0;
      writefln ("DTK initializing");
      if (!initialized)
                _initialized =(cGtkInit(0, null) != 0);
      if (!initialized)writefln  ("initialization failed");
   }
   this(string[] args)
   {  char*[]  argPs;
      argPs.length   =  args.length + 1;
      argPs.length   =  0;
      foreach  (arg; args)
      {  argPs ~= toStringz(arg);   }

      writefln ("next step is C");
      if (!initialized)
            _initialized   =
                (cGtkInit   (args.length, argPs.ptr) != 0);
      if (!initialized)writefln  ("initialization failed");
   }

   bool  initialized()  {  return   _initialized;  }
}

The C routine:
#include <stdlib.h>
#include <stdio.h>

int   cGtkInit (int argc, char** argv)
{  int   i, j;
   printf   ("cGtkInit before initialization\n");
   printf   ("argv[%d] = \n", argc);
   printf   (".1......................................\n");
   for   (i = 0;  i < argc;   i++)
   {  printf   ("\t%d : ", i);   fflush(stdout);
      for   (j = 0;  j < 256; j++)
      {  if (argv[i][j] != 0)
         {  printf   ("%c", argv [i][j]);
            fflush(stdout);
         }
         else
         {  printf   ("\n");
            break;
         }
      }
      printf   (".2......................................\n");
      printf   ("\t%d : %s\n", i, argv [i]);
   }
   printf   (".3-------------------------------....\n");
   gtk_init (argc, argv);
   printf   ("cGtkInit after initialization\n");
   return   1;
}

Yielding at execution time:
Hello World!
screen variable declared.
next step is C
cGtkInit before initialization
argv[1] =
.1......................................
        0 : ./scribble
.2......................................
        0 : ./scribble
.3-------------------------------....
Segmentation fault

Charles D Hixson wrote:
> I hope this is trivial, but I haven't been able to figure out how I'm 
It was trivial.  Once I imported the correct header file into the C code, things started working. (Well...producing useful error messages.)

> Here's my corrected trial (severely edited.):
> 

> The C routine:
> #include <stdlib.h>
> #include <stdio.h>
#include <gtk/gtk.h>

> 
> int   cGtkInit (int argc, char** argv)
...
>    printf   (".3-------------------------------....\n");
//>    gtk_init (argc, argv);
    gtk_init (&argc, &argv);
>    printf   ("cGtkInit after initialization\n");
>    return   1;
> }
> 
> Yielding at execution time:


Hello World!
screen variable declared.
next step is C
cGtkInit before initialization
char*[1] argv =
.1......................................
        argv [0] : './scribble'
.2......................................
        argv [0] : "./scribble"
.3-------------------------------....
cGtkInit after initialization
screen variable initialized.
Screen initialized
in routine amain
    gtk_init (&argc, &argv);