Re: [libvirt] [PATCH] Change/create solution and project for Visual Studio and MonoDevelop for C# bindings

2010/10/19 <arnaud.champion(a)devatom.fr&gt;: > Hi, > > here are 2 patches for C# libvirt bindings. > > These patches create a new solution/project couple for Visual Studio 2010 > with also a sample code and a solution/project couple for MonoDevelop > with a > sample code also. > > The sample code have been tested under .Net/Windows, Mono/Windows and > Mono/Linux. And it works, the sample code consist of the using au > virConnectOpenAuth and callback handling. It connect to a URI (I have > made > my tests with ESX hypervisor only) and list domains in a listbox. > > So, to summarize, code work under linux or windows, the binary library > name > depends of a project directive (a kind of pragma). When the directive > WINDOWS is declared, DllImport will try to find "libvirt-0.dll" (for > windows) otherwise it looks for "libvirt.so.0" (for linux). For now, in > the > same manner, when the directive WINDOWS is declared, we find _strdup in > "msvcrt.dll" otherwise we look in "libc.so.6". This makes the resulting binary platform dependent. I asked a friend about this and he suggested to use Mono's dllmap feature [1]. It allows you to stick with [DllImport("libvirt-0.dll")] in the code for .Net and have Mono use libvirt.so.0 on Linux and libvirt.dylib on OSX. This result in a platform independent binary regarding this issue. [1] http://www.mono-project.com/Config_DllMap > I'm currently trying to remove strdup call by Custom Marshaling but it > seems > that .Net (or Mono anyway) doesn't allow to use custom marshaler with > structure (and we need it for virConnectCredential structure). If anyone > had > an idea... Regarding this issue my friend suggested to stop libvirt from taking ownership of cred.result. We could do that by making virConnectOpenAuth take a new VIR_CONNECT_COPY_CRED_RESULT (or VIR_CONNECT_DONT_FREE_CRED_RESULT or VIR_CONNECT_CONST_CRED_RESULT) flag that lets libvirt internally strdup() cred.result before passing it to the driver. That way the C# bindings could pass a managed string as cred.result and we don't need to Marshal.StringToHGlobalAuto() and strdup in C# at all. Or we could make libvirt take a custom free function to free cred.result instead of free(). That way Marshal.FreeHGlobal could be used or no free function at all and you pass a managed string to it. This would probably require a new version of virConnectOpenAuth and I consider this as too invasive. Another possibility would be to add a public virAlloc to libvirt that C# can use to allocate memory that can be freed using free(). Matthias