VC++ Example: Loading DLLs LoadLibrary and GetProc

参考：#

#include
#include
#include

//GetProcAddresses
//Argument1: hLibrary - Handle for the Library Loaded
//Argument2: lpszLibrary - Library to Load
//Argument3: nCount - Number of functions to load
//[Arguments Format]
//Argument4: Function Address - Function address we want to store
//Argument5: Function Name -  Name of the function we want
//[Repeat Format]
//
//Returns: FALSE if failure
//Returns: TRUE if successful
BOOL GetProcAddresses( HINSTANCE *hLibrary,
       LPCSTR lpszLibrary, INT nCount, ... )
{
 va_list va;
 va_start( va, nCount );

 if ( ( *hLibrary = LoadLibrary( lpszLibrary ) )
  != NULL )
 {
  FARPROC * lpfProcFunction = NULL;
  LPSTR lpszFuncName = NULL;
  INT nIdxCount = 0;
  while ( nIdxCount < nCount )
  {
   lpfProcFunction = va_arg( va, FARPROC* );
   lpszFuncName = va_arg( va, LPSTR );
   if ( ( *lpfProcFunction = GetProcAddress( *hLibrary, lpszFuncName ) ) == NULL )
   {
    lpfProcFunction = NULL;
    return FALSE;
   }
   nIdxCount++;
  }
 }
 else
 {
  va_end( va );
  return FALSE;
 }
 va_end( va );
 return TRUE;
}

 

typedef int ( WINAPI *MESSAGEBOX )  ( HWND , LPCSTR, LPCSTR, DWORD );
typedef int ( WINAPI *MESSAGEBOXEX )( HWND , LPCSTR, LPCSTR, DWORD , WORD );
typedef BOOL(WINAPI *ISCHARUPPER) (TCHAR );
typedef LPTSTR ( WINAPI *CHARUPPER )( LPTSTR );

void main(void)
{
 
 MESSAGEBOX  lpfMsgBox = NULL;
 MESSAGEBOXEX lpfMsgBoxEx = NULL;
 CHARUPPER lpfCharUpper = NULL;
 ISCHARUPPER lpfIsCharUpper = NULL;

 HINSTANCE hLib;
 if(GetProcAddresses( &hLib, "User32.dll", 4,
  &lpfMsgBox, "MessageBoxA",
  &lpfMsgBoxEx, "MessageBoxExA" ,
  &lpfCharUpper, "CharUpperA",
  &lpfIsCharUpper, 413/*"IsCharUpperA"*/)) 参考depends,以序号方式加载，
 {
  //lpfMsgBox( 0, "Test1", "Test1", MB_OK );
  //lpfMsgBoxEx( 0, "Test2", "Test2", MB_OK, MAKELANGID( LANG_ENGLISH, SUBLANG_ENGLISH_US ) );

  char aa[120] = "aB";
  LPTSTR lpsz = "asddddffe";
  BOOL b = IsCharUpper( 'A');
  b = lpfIsCharUpper( 'b');

  CharLowerA(aa);
  lpfCharUpper(aa);
  //strcpy(aa, CharUpper("asddddffe"));

  printf("result = %s\n", lpsz); 
  
 }
 if ( hLib != NULL )
  FreeLibrary( hLib );
 
}