我有在Delphi上编写的DLL。我只有没有头文件的DLL,所以我动态加载它。 (对C ++项目)
HMODULE hLib = LoadLibrary(L"LibName.dll");
if (!hLib) {
//Throw error
}
DLL提供的功能:
function DataToFile(AddressName: PChar; Request: PChar;
RequestSize: integer; ResultFile: PChar;
ErrorBuf: PChar; ErrorBufSize: integer):BOOL;stdcall;
function DataToStream(AddressName: PChar; Request: PChar;
RequestSize: integer; ResultStream: IStream;
ErrorBuf: PChar; ErrorBufSize: integer):BOOL;stdcall;
我的Visual Studio代码(C ++):
typedef bool(__stdcall* f_DataToFile)(
char*, //AddressName: PChar
char*, //Request: PChar
int, //RequestSize: integer
char*, //FileName: PChar
char*, //ErrorBuf: PChar
int); //ErrorBufSize: integer);
typedef bool(__stdcall* f_DataToStream)(
char*, //AddressName: PChar
char*, //Request: PChar
int, //RequestSize: integer
std::istream &, //ResultStream: IStream
char*, //ErrorBuf: PChar
int); //ErrorBufSize: integer);
......获取功能。地址:
//load DataToFile
f_DataToFile DataToFile = (f_DataToFile) GetProcAddress(hLib, "DataToFile");
if (!DataToFile) { //throw error
}
//load DataToStream
f_DataToStream DataToStream = (f_DataToStream) GetProcAddress(hLib, "DataToStream");
if (!DataToStream) { //throw error
}
...设置数据:
char* AddressName = _strdup("127.0.0.1:1234"); //AddressName: PChar
char* Request = _strdup("<?xml request... >"); //Request: PChar
int RequestSize = strlen(Request); //RequestSize: integer
char* ResultFile = _strdup("exportpath\\output.xml"); //FileName: PChar
char* ErrorBuf = new char[255]; //ErrorBuf: PChar
int ErrorBufSize = 255; //ErrorBufSize: integer);
std::filebuf(buffer);
std::istream ResultStream(&buffer);
...第一个功能正常工作
bool reesult1= (DataToFile)(AddressName, Request, RequestSize, ResultFile, ErrorBuf, ErrorBufSize);
...我在第二次执行函数时遇到问题 -
bool reesult2= (DataToStream)(AddressName, Request, RequestSize, ResultStream, ErrorBuf, ErrorBufSize);
它正在编译,但在运行时会提供访问冲突。
有人可以帮助我 - 如何正确使用(Delphi)的IStream数据类型?
当我将ResultStream声明为nullptr指针并使用错误的连接地址调用DataToStream函数时,函数返回“连接错误” - 因此它被正确导入并且主要问题是从函数返回IStream。
您对IStream
的翻译不正确。 DLL正在使用COM IStream
interface。你无法用C ++的std::istream
类替换它。您需要使用实现IStream
接口的COM对象。要以IStream
身份访问文件,可以使用Win32 SHCreateStreamOnFileEx()
函数。
感谢Remy Lebeau!
HRESULT GetFileStream(
_In_ LPCWSTR fullFileName,
_Outptr_ IStream** stream)
{
HRESULT hr = S_OK;
// Create stream for writing the file
if (SUCCEEDED(hr))
{
hr = SHCreateStreamOnFileEx(
fullFileName,
STGM_CREATE | STGM_WRITE | STGM_SHARE_EXCLUSIVE,
0, // default file attributes
TRUE, // create file if it does not exist
NULL, // no template
stream);
}
return hr;
}
在typedef中:
IStream *, //ResultStream: IStream
..
LPCWSTR filename = L"path\\to\\file.txt";
IStream* ResultStream = NULL;
HRESULT hr = GetFileStream(filename, &ResultStream);
..
bool result = (CallRK7XMLRPCToStream)(AddressName, Request, RequestSize, ResultStream, ErrorBuf, ErrorBufSize);
这是使用SHCreateStreamOnFileEx的一个很好的例子: