• Paul Runde (18/18) May 18 2004 This works per documentation:
• Andy Friesen (16/18) May 18 2004 It's a piece of global data just like any other. It's equivalent to the...

Paul Runde <prunde consolidated.net> writes:

This works per documentation:

void function(int) dg;

void dothis(int x)
{
    printf("%d\n", x);
}

void main(char[][] args)
{
    dg = &dothis;
    dg(5);
}

However, if I put the declaration of dg in another file (test2.d in this 
  case) I get:

Error 42: Symbol undefined _D5test22dgPFiZv

It works if I put test2.d in the build command line, but why is the 
linker looking for a function pointer?

Thanks,
Paul

Andy Friesen <andy ikagames.com> writes:

Paul Runde wrote:
 It works if I put test2.d in the build command line, but why is the 
 linker looking for a function pointer?

It's a piece of global data just like any other.  It's equivalent to the 
C++:

test.cpp:

    #include "test2.h"

    void dothis(int x) { printf("%d\n", x); }

    int main(char** args) {
       dg = &dothis;
       dg(5);
    }

test2.cpp:
    void (*dg)(int);

test2.h:
    extern void (*dg)(int);

The difference is that D doesn't need a separate .h file.

  -- andy