Creating C++ DLL

TN1001

This example creates a class called base in testdll.cpp which is placed into a DLL.

Main in sample.c instantiates class base and calls a function in base to print out a message. C++ exception handling from a DLL is demonstrated by having the function do a throw which is caught in a catch block in main.

Mangled names apprear in the IMPORT section of sample.def below.

1. use "cppfilt /B /P sample.obj" to dump mangled names
2. build a library using sample.obj and get a listing using lib.exe
3. there are some utilities programs available that can dump obj names

SOURCE

dlltest.hpp

class base {
  public:
    void func(void);
    ~base(void);
    class bomb{
      public:
        bomb(int i) { }
    };
};

dlltest.cpp

#include  <stdio.h>
#include  "dlltest.hpp"

#pragma export(base::func(void))
#pragma export(base::~base(void))

base::~base(void) {
   printf("in base destructor\n");
}

void base::func(void) {
   printf("in base func\n");
   throw bomb(1);
}

dlltest.def

LIBRARY DLLTEST INITINSTANCE
DESCRIPTION 'Classes Dynamic Linking library'
PROTMODE
DATA        MULTIPLE READWRITE LOADONCALL
CODE        LOADONCALL

sample.cpp

#include <stdio.h>
#include "dlltest.hpp"

void main()
{
   base *b = new base();
   printf("after new\n");
   try {
     b->func();
   }
   catch (base::bomb x) {
     printf("caught\n");
   }
  printf("after d->func()\n");

  delete b;
  printf("after delete b\n");
}

sample.def

NAME SAMPLE WINDOWCOMPAT
IMPORTS
  dlltest.__dt__4baseFv
  dlltest.func__4baseFv

COMPILE OPTIONS

icc -Gm+ -Fd -Ge-  dlltest.cpp dlltest.def
icc -Gm+ -Fd       sample.cpp sample.def

various combinations of -Gd+ -Gm are possible depending on the desired configuration.

OUTPUT

  after new
  in base func
  caught
  after d->func()
  in base destructor
  after delete b