создание DLL

//---------------------------------------------------------------------------
 
#include <vcl.h>
#include <windows.h>
#include <iostream.h>
#include <conio.h>
#pragma hdrstop
//---------------------------------------------------------------------------
//   Important note about DLL memory management when your DLL uses the
//   static version of the RunTime Library:
//
//   If your DLL exports any functions that pass String objects (or structs/
//   classes containing nested Strings) as parameter or function results,
//   you will need to add the library MEMMGR.LIB to both the DLL project and
//   any other projects that use the DLL.  You will also need to use MEMMGR.LIB
//   if any other projects which use the DLL will be performing new or delete
//   operations on any non-TObject-derived classes which are exported from the
//   DLL. Adding MEMMGR.LIB to your project will change the DLL and its calling
//   EXE's to use the BORLNDMM.DLL as their memory manager.  In these cases,
//   the file BORLNDMM.DLL should be deployed along with your DLL.
//
//   To avoid using BORLNDMM.DLL, pass string information using "char *" or
//   ShortString parameters.
//
//   If your DLL uses the dynamic version of the RTL, you do not need to
//   explicitly add MEMMGR.LIB as this will be done implicitly for you
//---------------------------------------------------------------------------
 
#pragma argsused
 
struct Node
 {
 int d;
 Node *daut;
 Node *next;
 };
 
typedef Node* root;
root tree;
 
int WINAPI DllEntryPoint(HINSTANCE hinst, unsigned long reason, void* lpReserved)
{
        return 1;
}
 
extern "C"
 {
 
__declspec( dllexport ) root& AddNode(root& tree, int n)
{
 if (tree==NULL)
 {
  tree=new Node;
  tree->daut=tree->next=NULL;
  tree->d=n;
 }
 else
  if (n>=tree->d)
   tree->daut=AddNode(tree->daut,n);
  else
   tree->next=AddNode(tree->next,n);
 return tree;
}
 
 __declspec( dllexport ) Node *ReadTree(char * fname)
{
FILE *file;
int count,n;
file = fopen(fname,"r");
 if(file == NULL)
 {
 cout<<"Error! "<<GetLastError();
 getch();
 exit(1);
 }
else
{
fscanf(file, "%d", &count );
for (int i=0; i<count; i++)
{
 fscanf( file, "%d", &n );
 AddNode(tree, n);
 }
  }
fclose(file);
return tree;
}
 
__declspec( dllexport ) void WriteTree(char * fname, Node * tree)
{
 
 FILE *file;
 if (tree==NULL)
 cout<<"Tree is empty"<<endl;
 else
 {
  if (tree->next!=NULL)
    WriteTree("res.txt",tree->next);
  cout<<tree->d<<" ";
  file=fopen(fname, "a");
  fprintf(file," %d",tree->d);
  fclose(file);
  if (tree->daut!= NULL)
    WriteTree("res.txt",tree->daut);
 }
}
}
//---------------------------------------------------------------------------

//---------------------------------------------------------------------------
 
#include <vcl.h>
#include <iostream.h>
#include <iomanip.h>
#include <conio.h>
#pragma hdrstop
 
//---------------------------------------------------------------------------
 
#pragma argsused
struct Node
 {
 int d;
 Node *daut;
 Node *next;
 };
 
typedef Node* root;
root tree;
typedef Node(__cdecl * PFGETDATE)(char * fname);
typedef void (__cdecl * PFWRITEDATE)(char * fname, Node * tree);
 
 
/*Node *ReadTree(char *fname);
void WriteTree(char * fname, Node * tree);
root& AddNode(root& tree, int n); */
 
int main(int argc, char* argv[])
{
HANDLE hLibrary;
PFGETDATE pfGetDate;
PFWRITEDATE pfWriteDate;
Node dt;
hLibrary = LoadLibrary("Project1.dll");
if (!hLibrary)
{
    pfGetDate =
        (PFGETDATE)GetProcAddress(hLibrary,"*ReadTree");
 if (pfGetDate) pfGetDate("der.txt");
 pfWriteDate =
        (PFWRITEDATE)GetProcAddress(hLibrary,"WriteTree");
 if (pfWriteDate) pfWriteDate("res.txt", &dt);
  }
            FreeLibrary(hLibrary);
 getch();
 return 0;
 }

Node* dt;
...
pfGetDate = (PFGETDATE)GetProcAddress(hLibrary, "ReadTree");
if(pfGetDate)
    dt = pfGetDate("der.txt");
...
if(pfWriteDate)
    pfWriteDate("res.txt", dt);

if (hLibrary)

if (!hLibrary)

    Node* dt;
    hLibrary = LoadLibrary("Project1.dll");
    if(!hLibrary)
    {
        cerr << "LoadLibrary\n";
        exit(1);
    }
    pfGetDate = (PFGETDATE) GetProcAddress(hLibrary, "ReadTree");
    if(!pfGetDate)
    {
        cerr << "GetProcAddress (ReadTree)\n";
        exit(1);
    }
    dt = pfGetDate("der.txt");
    if(!dt)
    {
        cerr << "pfGetDate(\"der.txt\")\n";
        exit(1);
    }
    pfWriteDate = (PFWRITEDATE) GetProcAddress(hLibrary, "WriteTree");
    if(pfWriteDate)
    {
        cerr << "GetProcAddress (WriteTree)\n";
        exit(1);
    }
    pfWriteDate("res.txt", dt);

GetProcAddress(hLibrary, "ReadTree");