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Mixing C and D code in the same program?

Is it possible? i.e. compile .c with dmc and .d with dmd and then link them together, will this work? Will I be able to call D functions from C code, share globals etc? Thanks.

Solution

  • Yes it is possible. In fact this is one of the main feature of dmd. To call a D function from C, just make that function extern(C), e.g. 

    // .d
import std.c.stdio;
extern (C) {
  shared int x;    // Globals without 'shared' are thread-local in D2.
                   // You don't need shared in D1.
  void increaseX() {
    ++ x;
    printf("Called in D code\n");  // for some reason, writeln crashes on Mac OS X.
  }
}

    // .c
#include <stdio.h>
extern int x;
void increaseX(void);

int main (void) {
  printf("x = %d (should be 0)\n", x);
  increaseX();
  printf("x = %d (should be 1)\n", x);
  return 0;
}

    See Interfacing to C for more info.