load dll 简单方式 （收集）

http://blog.csdn.net/aca_jingru/article/details/2524697

本文转自codeprojcet  <a href="http://www.codeproject.com/kb/dll/dllease.aspx">http://www.codeproject.com/KB/DLL/dllease.aspx</a>

load dll也就是load dll中的函数,一般是loadlibrary,GetProcAddress,每一步都要判断函数返回是否正确,比较繁琐,

该作者干脆做了个封装,将这些重复步骤封装到一个bool的函数中,这样只要在if语句中调用一下可以了,具体来看代码:这里用到了c语言的可变参数,对此俺也不是很了解

 

//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;
}

使用的例子:

<pre class="csharp" name="code"><pre class="csharp" name="code">#include <windows.h></windows.h>

typedef int ( WINAPI *MESSAGEBOX )
    ( HWND , LPCSTR, LPCSTR, DWORD );
typedef int ( WINAPI *MESSAGEBOXEX )
    ( HWND , LPCSTR, LPCSTR, DWORD , WORD );

void main(void)
{
    MESSAGEBOX lpfMsgBox = NULL;
    MESSAGEBOXEX lpfMsgBoxEx = NULL;
    HINSTANCE hLib;
    if(GetProcAddresses( &hLib, "User32.dll", 2,
        &lpfMsgBox, "MessageBoxA",
        &lpfMsgBoxEx, "MessageBoxExA" ) )
    {
        lpfMsgBox( 0, "Test1", "Test1", MB_OK );
        lpfMsgBoxEx( 0, "Test2", "Test2", MB_OK,
            MAKELANGID( LANG_ENGLISH, SUBLANG_ENGLISH_US ) );
    }
    if ( hLib != NULL )
        FreeLibrary( hLib );
}

是不是很好用呢 囧