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Daniel Doubrovkine

aka dB., CTO at artsy.net, fun at playplay.io, NYC

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Let’s build JNA on a Windows AMD 64. I am always confused about which Cygwin packages I actually need to do that. Every time I get it wrong. So this is what you need beyond the basic Cygwin installation: make, gcc-mingw, mingw64-i686. The latter is important, you need the i686 packages, not the cross-platform x86-64 ones.

With these you would still get a failure building libffi, stating that the C compiler can’t produce binaries. Pursuing that I found that libffi will use Visual Studio to build itself on AMD64. You need Visual Studio 2008, including the X64 Compiler and Tools that aren’t installed by default.

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The problem persists! Libffi uses cl.sh that does magical things with cl.exe. I managed to hack around it to finally get a Visual Studio cl.exe to work in this environment, but still couldn’t get libffi to build. At this point I gave up trying to get an AMD64 build. But I do have another 64-bit machine where build works!

The difference is in JAVA_HOME. With 32-bit Java libffi will build a 32-bit version. With 64-bit Java it will want to be a native 64-bit thing. Installing 32-bit Java and setting JAVA_HOME to c:\Program Files (x86)\Java\jdk1.6.0_22 solves the problem. While this is not a 64-bit build it runs fine on Win-64, enough for development and debugging.