在VS2008下用ACE创建及使用DLL（动态链接库）

在VS2008下用ACE创建及使用DLL（动态链接库）

下面是 ACE-6.0.0 提供的创建及使用DLL的实例，代码所在目录：\ACE-6.0.0\ACE_wrappers\examples\Export 。

DLL的代码：

1. dll.h 文件

// $Id: dll.h 80826 2008-03-04 14:51:23Z wotte $// To use the export macros with a DLL, a file will need to be// created (see ACE_wrapper/bin/generate_export_file.pl) and// included.  This file defines Test_Export (and the// TEST_SINGLETON_* macros).#include "test_export.h"#include "ace/Singleton.h"#include "ace/Null_Mutex.h"#define RETVAL 42// To expose a function outside of a DLL, use the *_Export// at the beginning of the function declaration.Test_Export int test_function ();// To expose data, put use the *Export at the beginning// of the variable declaration.  The extern is required when// building static libraries.extern Test_Export int test_variable;// To expose a class, put the *_Export between "class"// and the class name.class Test_Export test_class{public:  int method ();};// ACE_Singleton and its relatives are special cases.  The problem is// that ACE_Singleton is a template.  If the singleton is used in both// the DLL and the executable linking the DLL, then two instances of// the singleton will be used (which defeats the purpose of a Singleton).//// This occurs because the ACE_Singleton template is expanded in both// places because Visual C++ and Borland C++ do this automatically by// including the template source.  This in turn creates two copies of// the static member variable.//// So to get around this problem, the *_SINGLETON_DECLARE macro is// used to instruct the compiler to not create the second copy in the// program.  This macro solution does not work for Borland C++, so for// this compiler you must explicitly disable the template instantiation// using a #pragma (or use the other workaround below).//// Another workaround for this is to not to expose the Singleton itself// to the outside world, but to instead supply a function or static// member function that returns the singleton to the executable// (like get_dll_singleton () does below).#if defined (__BORLANDC__)# if !defined (TEST_BUILD_DLL)#   pragma option push -Jgx# endif#endifTEST_SINGLETON_DECLARE (ACE_Singleton, test_class, ACE_Null_Mutex)#if defined (__BORLANDC__)# if !defined (TEST_BUILD_DLL)#   pragma option pop# endif#endiftypedef ACE_Singleton<test_class, ACE_Null_Mutex> TEST_SINGLETON;Test_Export test_class *get_dll_singleton ();

 

2. dll.cpp 文件

// $Id: dll.cpp 80826 2008-03-04 14:51:23Z wotte $#include "dll.h"int test_variable = 0;inttest_function (){  test_variable = RETVAL;  return RETVAL;}inttest_class::method (){  return RETVAL;}test_class *get_dll_singleton (){  return TEST_SINGLETON::instance ();}#if defined (ACE_HAS_EXPLICIT_STATIC_TEMPLATE_MEMBER_INSTANTIATION)template ACE_Singleton<test_class, ACE_Null_Mutex> *ACE_Singleton<test_class, ACE_Null_Mutex>::singleton_;#endif /* ACE_HAS_EXPLICIT_STATIC_TEMPLATE_MEMBER_INSTANTIATION */

测试上面DLL的代码：

1. test_export.h 文件

// -*- C++ -*-// $Id: test_export.h 80826 2008-03-04 14:51:23Z wotte $// Definition for Win32 Export directives.// This file is generated automatically by// generate_export_file.pl// ------------------------------#if !defined (TEST_EXPORT_H)#define TEST_EXPORT_H#include "ace/config-all.h"#if defined (ACE_AS_STATIC_LIBS) && !defined (TEST_HAS_DLL)#  define TEST_HAS_DLL 0#endif /* ACE_AS_STATIC_LIBS && ! TEST_HAS_DLL */#if !defined (TEST_HAS_DLL)#define TEST_HAS_DLL 1#endif /* ! TEST_HAS_DLL */#if defined (TEST_HAS_DLL)#  if (TEST_HAS_DLL == 1)#    if defined (TEST_BUILD_DLL)#      define Test_Export ACE_Proper_Export_Flag#      define TEST_SINGLETON_DECLARATION(T) ACE_EXPORT_SINGLETON_DECLARATION (T)#      define TEST_SINGLETON_DECLARE(SINGLETON_TYPE, CLASS, LOCK) ACE_EXPORT_SINGLETON_DECLARE(SINGLETON_TYPE, CLASS, LOCK)#    else#      define Test_Export ACE_Proper_Import_Flag#      define TEST_SINGLETON_DECLARATION(T) ACE_IMPORT_SINGLETON_DECLARATION (T)#      define TEST_SINGLETON_DECLARE(SINGLETON_TYPE, CLASS, LOCK) ACE_IMPORT_SINGLETON_DECLARE(SINGLETON_TYPE, CLASS, LOCK)#    endif /* TEST_BUILD_DLL */#  else#    define Test_Export#    define TEST_SINGLETON_DECLARATION(T)#    define TEST_SINGLETON_DECLARE(SINGLETON_TYPE, CLASS, LOCK)#  endif   /* ! TEST_HAS_DLL == 1 */#else#  define Test_Export#  define TEST_SINGLETON_DECLARATION(T)#  define TEST_SINGLETON_DECLARE(SINGLETON_TYPE, CLASS, LOCK)#endif     /* TEST_HAS_DLL */#endif     /* TEST_EXPORT_H */// End of auto generated file.

2. test.cpp 文件

// $Id: test.cpp 80826 2008-03-04 14:51:23Z wotte $#include "dll.h"#include <ace/streams.h>intACE_TMAIN (int, ACE_TCHAR *[]){  int failure_count = 0;  test_class my_test_class;  // Tet out the export of a class.  I don't see  // How this can fail at runtime (rather it would  // probably give link errors), but just in case...  cout << "Method Test: ";  if (my_test_class.method () != RETVAL)    {      cout << "Failed" << endl;      ++failure_count;    }  else    cout << "Succeeded" << endl;  // Test out the export of a function.  Like above,  // I don't know how this can fail at runtime.  cout << "Function Test: ";  if (test_function () != RETVAL)    {      cout << "Failed" << endl;      ++failure_count;    }  else    cout << "Succeeded" << endl;  // Also test out the export of data.  cout << "Variable Test: ";  if (test_variable != RETVAL)    {      cout << "Failed" << endl;      ++failure_count;    }  else    cout << "Succeeded" << endl;  // Test out the ACE_Singleton export by checking to see  // that we have the same instance pointer as the DLL does.  // This can fail at runtime.  cout << "Singleton Test: ";  if (TEST_SINGLETON::instance () != get_dll_singleton ())    {      cout << "Failed" << endl;      ++failure_count;    }  else    cout << "Succeeded" << endl;  getchar();  // Return the number of failures  return failure_count;}