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Re: Possible to use pinvoke to call DLL built with cygwin

Sammy Yu wrote:
Hi guys,
   I'm trying to port an application onto Windows that was originally
developed for UNIX using rpc, pthreads, and AF_UNIX sockets.  I have
used cygwin to compile this application successfully.  One of the
components built is a DLL which I want to invoke from a C Sharp
application.  However, the application crashes whenever I call this
DLL via pinvoke in C Sharp.

************** Exception Text ************** System.DllNotFoundException: Unable to load DLL 'perm.dll': Invalid access to memory location. (Exception from HRESULT: 0x800703E6) at () at WinPcapRedirectorUI.MainForm.statisticsButton_Click(Object sender, EventArgs e) in C:\eclipse\workspace\winperm\WinPcapRedirectorUI\MainForm.cs:line 74 at System.Windows.Forms.Control.OnClick (EventArgs e) at System.Windows.Forms.Button.OnClick(EventArgs e) at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)

I verified that the cygwin*.dll are in the path. I made a strip down version of a dll, it exhibited the same behavior. Next, I compiled the library with -mno-cygwin flag which surprisingly worked. I suspect that cygwin1.dll does not work with pinvoke. Can anybody confirm this is true? I prefer not to have to port the native application to Visual C or mingw32 as there are a lot of rpc and AF_UNIX sockets. Are there any other alternatives? Thanks in advance for your help!

You need to initialize the DLL.  Loading the Cygwin DLL from a non-Cygwin
app doesn't initialize it automatically.  Only Cygwin apps do that.  Off
the top of my head, I don't recall the details but this has been discussed
before in the email archives, if you want to poke around a bit for the

-- Larry Hall RFK Partners, Inc. (508) 893-9779 - RFK Office 216 Dalton Rd. (508) 893-9889 - FAX Holliston, MA 01746

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