Because apparently GHC works much better on Linux than Windows, I switched to that platform. I'm currently trying Fedora 8. So now I'm completely alone in the dark: no experience with Haskell, no experience with Linux; I left decades of experience with Microsoft products behind me ;-) I tried compiling GFLW (used by SOE) and a Haskell test app on my laptop, and that worked fine. Then I installed Fedora on my desktop, installed all development tools, and GLFW (both the C library and Haskell wrapper) also compiled and linked fine, but when trying to link the test app to GLFW, I got linker errors (see below). It seems these symbols are defined in libXrandr, but I have both the binary as the devel package installed: [root@localhost dev]# yum list installed | grep Xrandr libXrandr.i386 1.2.2-1.fc8 installed libXrandr-devel.i386 1.2.2-1.fc8 installed So I have no idea what to do. The main difference between the laptop and desktop is that I installed the NVidia drivers on the desktop manually (first installed the kernel-devel package, and then downloaded and installed the linux driver from the nvidia website) Any hints? Thanks, Peter Linker errors reported by ghc --make Main.hs: /usr/local/lib/GLFW-0.1/ghc-6.8.2/libHSGLFW-0.1.a(x11_window.o): In function `_glfwPlatformRefreshWindowParams': x11_window.c:(.text+0x803): undefined reference to `XRRGetScreenInfo' x11_window.c:(.text+0x80d): undefined reference to `XRRConfigCurrentRate' x11_window.c:(.text+0x81b): undefined reference to `XRRFreeScreenConfigInfo' /usr/local/lib/GLFW-0.1/ghc-6.8.2/libHSGLFW-0.1.a(x11_window.o): In function `_glfwPlatformCloseWindow': x11_window.c:(.text+0xb7a): undefined reference to `XRRGetScreenInfo' x11_window.c:(.text+0xb9d): undefined reference to `XRRSetScreenConfig' x11_window.c:(.text+0xba6): undefined reference to `XRRFreeScreenConfigInfo' /usr/local/lib/GLFW-0.1/ghc-6.8.2/libHSGLFW-0.1.a(x11_window.o): In function `_glfwPlatformPollEvents': x11_window.c:(.text+0x115b): undefined reference to `XRRUpdateConfiguration' /usr/local/lib/GLFW-0.1/ghc-6.8.2/libHSGLFW-0.1.a(x11_window.o): In function `_glfwPlatformOpenWindow': x11_window.c:(.text+0x1fa5): undefined reference to `XRRSelectInput' /usr/local/lib/GLFW-0.1/ghc-6.8.2/libHSGLFW-0.1.a(x11_fullscreen.o): In function `_glfwPlatformGetVideoModes': x11_fullscreen.c:(.text+0x1ca): undefined reference to `XRRGetScreenInfo' x11_fullscreen.c:(.text+0x1db): undefined reference to `XRRConfigSizes' x11_fullscreen.c:(.text+0x219): undefined reference to `XRRFreeScreenConfigInfo' /usr/local/lib/GLFW-0.1/ghc-6.8.2/libHSGLFW-0.1.a(x11_fullscreen.o): In function `_glfwSetVideoModeMODE': x11_fullscreen.c:(.text+0x329): undefined reference to `XRRGetScreenInfo' x11_fullscreen.c:(.text+0x344): undefined reference to `XRRConfigCurrentConfiguration' x11_fullscreen.c:(.text+0x394): undefined reference to `XRRSetScreenConfigAndRate' x11_fullscreen.c:(.text+0x3ac): undefined reference to `XRRSetScreenConfig' /usr/local/lib/GLFW-0.1/ghc-6.8.2/libHSGLFW-0.1.a(x11_fullscreen.o): In function `_glfwGetClosestVideoMode': x11_fullscreen.c:(.text+0x3fa): undefined reference to `XRRGetScreenInfo' x11_fullscreen.c:(.text+0x408): undefined reference to `XRRConfigSizes' x11_fullscreen.c:(.text+0x48f): undefined reference to `XRRConfigRates' x11_fullscreen.c:(.text+0x4dc): undefined reference to `XRRFreeScreenConfigInfo' x11_fullscreen.c:(.text+0x512): undefined reference to `XRRFreeScreenConfigInfo' /usr/local/lib/GLFW-0.1/ghc-6.8.2/libHSGLFW-0.1.a(x11_fullscreen.o): In function `_glfwSetVideoModeMODE': x11_fullscreen.c:(.text+0x3be): undefined reference to `XRRFreeScreenConfigInfo' /usr/local/lib/GLFW-0.1/ghc-6.8.2/libHSGLFW-0.1.a(x11_init.o): In function `_glfwPlatformInit': x11_init.c:(.text+0xea): undefined reference to `XRRQueryExtension' collect2: ld returned 1 exit status