Programming

/* classdef.h */
#ifndef __CLASSDEF_H__
#define __CLASSDEF_H__

class def
{
public:
  def();
  ~def();
  int member(void);
};

#endif/*__CLASSDEF_H__*/

/* classdef.cpp */
#include <stdio.h>
#include "classdef.h"

def::def()
{
  printf("Constructor\n");
}

def::~def()
{
  printf("Destructor\n");
}

int def::member(void)
{
  printf("def::member()\n");
  return(42);
}

/* usesclassdef.cpp */
#include <stdio.h>
#include "classdef.h"

int main(int argc, char *argv[])
{
  def *d=new def();

  printf("d->member() returns %d\n", d->member());
  delete d;
  return(0);
}

$ gcc -c classdef.cpp
$ gcc -shared classdef.o -o libclassdef.so
/usr/lib/gcc-lib/i386-pc-linux-gnu/3.3.6/../../../../i386-pc-linux-gnu/bin/ld: warning: creating a DT_TEXTREL in object.
$ ls
classdef.cpp  classdef.h  libclassdef.so  usesclassdef.cpp
$ g++ usesclassdef.cpp -L./ -lclassdef -o usesclassdef
$ ls
classdef.cpp  classdef.h  libclassdef.so  usesclassdef  usesclassdef.cpp
$ ./usesclassdef
./usesclassdef: error while loading shared libraries: libclassdef.so: cannot open shared object file: No such file or directory
$ LD_LIBRARY_PATH="./" ./usesclassdef
Constructor
def::member()
d->member() returns 42
Destructor
$