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POCall dll with C++ header from C#
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copied!<p>I'm trying to call a method in a dll which I have the C++ header for. I'm calling the dll from C#. The input is a string and the output is binary data. Any of the following 3 methods would probably work, I just don't know how to make any of them work all the way. The C# declaration is made by me, so they might not be correct</p> <p>1: I'm able to get the hGlobal, but I don't know how to get data from the handle.</p> <pre><code>//CMBT_LL_WINAPI INT DLLPROC LlConvertStringToHGLOBALW(LPCWSTR pszText, _PHGLOBAL phMemory); [DllImport("cmll15.dll", EntryPoint = "LlConvertStringToHGLOBALW", CharSet = CharSet.Unicode, ExactSpelling = true)] private static extern int _LlConvertStringToHGlobal32(string text, ref IntPtr handle); </code></pre> <p>2: </p> <pre><code>[DllImport("cmll15.dll", EntryPoint = "LlConvertStringToBLOBW", CharSet = CharSet.Unicode, ExactSpelling = true)] //CMBT_LL_WINAPI INT DLLPROC LlConvertStringToBLOBW(LPCWSTR pszText, _PUINT8 pBytes, UINT nBytes); private static extern int _LlConvertStringToBLOBW(string text, ref IntPtr pBytes, UInt32 nBytes); </code></pre> <p>3:</p> <pre><code>[DllImport("cmll15.dll", EntryPoint = "LlConvertStringToStreamW", CharSet = CharSet.Unicode, ExactSpelling = true)] //CMBT_LL_WINAPI INT DLLPROC LlConvertStringToStreamW(LPCWSTR pszText, _PISTREAM pStream); private static extern int _LlConvertStringToStreamW(string text, ref IntPtr pStream); </code></pre> <p>Updated, here is the code I think I will end up with.</p> <pre><code> [DllImport("kernel32.dll", SetLastError = true, ExactSpelling = true)] private static extern UIntPtr GlobalSize(IntPtr hMem); [DllImport("kernel32.dll", SetLastError = true, ExactSpelling = true)] public static extern IntPtr GlobalLock(IntPtr handle); [DllImport("kernel32.dll", SetLastError = true, ExactSpelling = true)] public static extern IntPtr GlobalUnlock(IntPtr handle); [DllImport("cmll15.dll", EntryPoint = "LlConvertStringToHGLOBALW", CharSet = CharSet.Unicode, ExactSpelling = true)] private static extern int _LlConvertStringToHGlobal32(string text, ref IntPtr handle); private static void Main(string[] args) { IntPtr dataHandle = IntPtr.Zero; _LlConvertStringToHGlobal32(Contents, ref dataHandle); try { var size = (uint) GlobalSize(dataHandle); var array = new byte[size]; IntPtr dataPtr = GlobalLock(dataHandle); try { Marshal.Copy(dataPtr, array, 0, array.Length); } finally { GlobalUnlock(dataPtr); } using (var fs = new FileStream("c:\\file.dat", FileMode.Create)) { fs.Write(array, 0, array.Length); } } finally { Marshal.FreeHGlobal(dataHandle); } } </code></pre>

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