subject_36716.htm

一些关于vc的问答

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序号：36716 发表者：小丫多多 发表日期：2003-04-17 22:17:44
<br>主题：求教显式加载DLL文件的问题！！
<br>内容：我正在做一个数据采集的软件，使用了一块pc总线数据采集控制卡。<BR>随该卡仅提供了一个DLL文件及一个在win2000下使用的驱动程序。<BR>安装完驱动之后，dll文件自动考入WINNT\SYSTEM32目录下。<BR>于是我在程序中显示加载了该DLL，具体代码如下：（我使用的是WIN2000系统）<BR>/////////////////////////////////////////////////////////////////////////////<BR>&nbsp;&nbsp;&nbsp;&nbsp;HINSTANCE hInstDll;<BR>&nbsp;&nbsp;&nbsp;&nbsp;unsigned short value;<BR>&nbsp;&nbsp;&nbsp;&nbsp;unsigned long time;<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;typedef unsigned short (*READCHDATA)(unsigned short, <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;unsigned char, unsigned long, unsigned long);<BR>&nbsp;&nbsp;&nbsp;&nbsp;typedef unsigned short (*QPCOUNTER)(void);<BR>&nbsp;&nbsp;&nbsp;&nbsp;typedef void (*OUTPORT)(unsigned short, unsigned char);<BR>&nbsp;&nbsp;&nbsp;&nbsp;typedef void (*DELAY)(unsigned long);<BR><BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;READCHDATA&nbsp;&nbsp;&nbsp;&nbsp;ReadChData;<BR>&nbsp;&nbsp;&nbsp;&nbsp;QPCOUNTER&nbsp;&nbsp;&nbsp;&nbsp;GetCounter;<BR>&nbsp;&nbsp;&nbsp;&nbsp;OUTPORT&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;OutPort;<BR>&nbsp;&nbsp;&nbsp;&nbsp;DELAY&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Delay;<BR><BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;hInstDll = GetModuleHandle("c:\\winnt\\system32\\k800.dll");<BR>&nbsp;&nbsp;&nbsp;&nbsp;if(hInstDll == NULL)<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;VERIFY(hInstDll = LoadLibrary("c:\\winnt\\system32\\k800.dll"));<BR>&nbsp;&nbsp;&nbsp;&nbsp;<BR>&nbsp;&nbsp;&nbsp;&nbsp;VERIFY(ReadChData =(READCHDATA)GetProcAddress(hInstDll, "read_ch_data"));<BR>&nbsp;&nbsp;&nbsp;&nbsp;VERIFY(GetCounter = (QPCOUNTER)GetProcAddress(hInstDll, "q_p_counter"));<BR>&nbsp;&nbsp;&nbsp;&nbsp;VERIFY(OutPort = (OUTPORT)GetProcAddress(hInstDll, "out_port"));<BR>&nbsp;&nbsp;&nbsp;&nbsp;VERIFY(Delay = (DELAY)GetProcAddress(hInstDll, "adelay"));<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;time = GetCounter();<BR>&nbsp;&nbsp;&nbsp;&nbsp;value = ReadChData(768, 0, 150, 30);<BR>&nbsp;&nbsp;&nbsp;&nbsp;OutPort(770, 0);<BR>&nbsp;&nbsp;&nbsp;&nbsp;Delay(10000);<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;VERIFY(FreeLibrary(hInstDll));<BR><BR>/////////////////////////////////////////////////////////////////////////////<BR>系统编译通过，运行时time = GetCounter();能正常运行，但一但运行到<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; value = ReadChData(768, 0, 150, 30);<BR>&nbsp;&nbsp;&nbsp;&nbsp;OutPort(770, 0);<BR>&nbsp;&nbsp;&nbsp;&nbsp;Delay(10000);<BR><BR>这类带有参数的函数时就会弹出消息框：debug error!<BR>说是函数调用方式不合适。<BR>不知为何？望高手赐教！！！万分感谢！！！！<BR>
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<font color=red>答案被接受</font><br>回复者：xiongli 回复日期：2003-04-17 23:28:38
<br>内容：可能是dll里面delay 函数参数声明跟你程序里面的参数声明不相同<BR>所以在最后函数返回的时候堆栈被破坏
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回复者：dr0 回复日期：2003-04-17 23:40:55
<br>内容：typedef unsigned short (*READCHDATA)(unsigned short, <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;unsigned char, unsigned long, unsigned long);<BR>&nbsp;&nbsp;&nbsp;&nbsp;typedef unsigned short (*QPCOUNTER)(void);<BR>&nbsp;&nbsp;&nbsp;&nbsp;typedef void (*OUTPORT)(unsigned short, unsigned char);<BR>&nbsp;&nbsp;&nbsp;&nbsp;typedef void (*DELAY)(unsigned long);<BR><BR>// try : typedef void(__stdcall *delay)(unsigned long);<BR>// I guess your dll will export __stdcall routines to support VB etc <BR>// the compiler will generaet __cdecl call convention if you reserve<BR>// the default settings. have a try ?<BR>2003-4-17 23:41:37