Hello, I have a GUI program that when I compile it and run it there are no problems. When I load it into GHCI and type, "main", it loads the main window but there are no window decorations and the program hangs to the point where I have to kill the ghci process. You see a spinning cursor when you mouse over the window. I found this old email regarding gtk2hs: http://web.archiveorange.com/archive/v/nDNOvMeDATtTGn026lbI I recompiled the program to use -threaded but the behavior is unchanged (if the email above describes my problem then I expected the compiled version to start having issues). What else can cause the hangs I'm seeing? I'm using the GLFW-b library on hackage and the program I'm trying to run are any of the executables from the nehe-tuts package (also on hackage). To reproduce my hangs, I think you need OSX (I didn't test this on windows or linux), and then type the following: {{{ mkdir -p ~/tmp/test cd ~/tmp/test cabal update cabal-dev install-deps nehe-tuts cabal unpack nehe-tuts cabal-dev ghci nehe-tuts-0.2.3/lesson01.hs *Main> main }}} Doing a force quit on ghci gives me a stack trace via the OSX crash reporting system. You'll find the relevant bits from that at the end of this email. What debugging techniques do I have at my disposal for figuring out what is going wrong here? At least one person has suggested that possibly ghci and the GUI bits of glfw are competing for input and conflicting with each other. If that's the case, how could I be sure and what would I do about it? Thanks, Jason {{{ Process: ghc [48045] Path: /Library/Frameworks/GHC.framework/Versions/7.0.3-x86_64/usr/lib/ghc-7.0.3/ghc UID: 502 Thread 84d5f8 DispatchQueue 1 User stack: 47 __semwait_signal + 10 (in libSystem.B.dylib) [0x7fff8760ef8a] Kernel stack: 46 semaphore_wait_continue + 0 [0x22a88f] 1 lo_alltraps + 454 [0x2a1976] 1 i386_astintr + 47 [0x2aacb4] 1 ast_taken + 247 [0x219432] 1 bsd_ast + 806 [0x48fea8] 1 postsig + 432 [0x48cfff] 1 exit1 + 449 [0x48187a] 1 task_terminate_internal + 242 [0x22ca4d] 1 ipc_space_destroy + 177 [0x215868] 1 ipc_right_clean + 397 [0x215256] 1 mach_notify_no_senders + 75 [0x23ff7b] 1 mach_msg_send_from_kernel_proper + 90 [0x21e0cb] 1 ipc_kmsg_send + 105 [0x210a86] 1 ipc_kobject_server + 267 [0x21dbfc] 1 iokit_notify + 154 [0x284eed] 1 iokit_client_died + 85 [0x571527] 1 com.apple.GeForce 6.3.0 + 47083 [0x830867eb] 1 com.apple.GeForce 6.3.0 + 305981 [0x830c5b3d] 1 com.apple.GeForce 6.3.0 + 258633 [0x830ba249] 1 OSObject::release() const + 25 [0x506759] 1 OSObject::taggedRelease(void const*) const + 32 [0x50673e] 1 com.apple.GeForce 6.3.0 + 253194 [0x830b8d0a] 1 com.apple.GeForce 6.3.0 + 251919 [0x830b880f] 1 com.apple.NVDAResman 6.3.0 + 453556 [0x83689bb4] 1 com.apple.NVDAResman 6.3.0 + 445937 [0x83687df1] 1 com.apple.NVDAResman 6.3.0 + 302211 [0x83664c83] 1 com.apple.NVDAResman 6.3.0 + 249957 [0x83658065] 1 com.apple.NVDAResman 6.3.0 + 112888 [0x836368f8] 1 com.apple.NVDAResman 6.3.0 + 111718 [0x83636466] 1 com.apple.nvidia.nv50hal 6.3.0 + 623157 [0x83e1a235] 1 com.apple.nvidia.nv50hal 6.3.0 + 605845 [0x83e15e95] 1 com.apple.nvidia.nv50hal 6.3.0 + 606056 [0x83e15f68] Thread 84d67e DispatchQueue 2 User stack: 46 start_wqthread + 13 (in libSystem.B.dylib) [0x7fff875edfc5] 46 _pthread_wqthread + 353 (in libSystem.B.dylib) [0x7fff875ee128] 46 _dispatch_worker_thread2 + 252 (in libSystem.B.dylib) [0x7fff875ee7fe] 46 _dispatch_queue_invoke + 185 (in libSystem.B.dylib) [0x7fff875eecd4] 46 kevent + 10 (in libSystem.B.dylib) [0x7fff875ed12a] Kernel stack: 46 kevent + 97 [0x47a681] Thread 84d5f9 User stack: 46 kevent64 + 10 (in libSystem.B.dylib) [0x7fff87687512] Kernel stack: 46 kevent + 97 [0x47a681] Thread 84d5fa User stack: 46 ??? [0x10681d9e8] 38 ??? [0x10a60403b] 37 CGLFlushDrawable + 67 (in OpenGL) [0x7fff819d3261] 37 gldFinish + 874 (in GeForceGLDriver) [0x2000d728a] 37 glcNoop + 1072 (in OpenGL) [0x7fff819d491c] 37 CGSFlushSurfaceWithOptions + 396 (in CoreGraphics) [0x7fff88fb81f9] 37 _CGSFlushSurfaceInline + 210 (in CoreGraphics) [0x7fff88fb848c] 37 mach_msg_trap + 10 (in libSystem.B.dylib) [0x7fff875d429a] 1 glfwSwapBuffers + 69 (in libglfw.dylib) [0x1036f6ba5] 1 _glfwPlatformPollEvents + 132 (in libglfw.dylib) [0x1036f26c4] 1 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 155 (in AppKit) [0x7fff88135751] 1 _DPSNextEvent + 103 (in AppKit) [0x7fff88135ba5] 8 ??? [0x109fc6d03] 8 glFlush_Exec + 133 (in GLEngine) [0x11c5b7150] 8 gldUpdateDispatch + 13841 (in GeForceGLDriver) [0x2000d6711] 8 IOConnectCallMethod + 325 (in IOKit) [0x7fff81ae3328] 8 io_connect_method + 490 (in IOKit) [0x7fff81b26ad2] 8 mach_msg_trap + 10 (in libSystem.B.dylib) [0x7fff875d429a] Kernel stack: 32 ipc_mqueue_receive_continue + 0 [0x210d84] 12 lo64_mach_scall + 77 [0x2a255d] 12 thread_setuserstack + 405 [0x295c17] 8 mach_msg_overwrite_trap + 274 [0x216f84] 8 ipc_kmsg_send + 105 [0x210a86] 8 ipc_kobject_server + 244 [0x21dbe5] 8 iokit_server_routine + 4669 [0x286610] 8 is_io_connect_method + 467 [0x56e2b3] 8 IOUserClient::externalMethod(unsigned int, IOExternalMethodArguments*, IOExternalMethodDispatch*, OSObject*, void*) + 909 [0x56d9ff] 8 shim_io_connect_method_scalarI_structureO + 455 [0x56d160] 8 com.apple.GeForce 6.3.0 + 49337 [0x830870b9] 8 com.apple.GeForce 6.3.0 + 310514 [0x830c6cf2] 8 com.apple.GeForce 6.3.0 + 64383 [0x8308ab7f] 8 IOLockSleep + 39 [0x53633c] 8 lck_mtx_sleep + 87 [0x221d42] 8 thread_block + 33 [0x227654] 8 thread_block_reason + 331 [0x2275c6] 8 thread_dispatch + 1966 [0x227327] 8 machine_switch_context + 659 [0x2a9adb] 4 mach_msg_overwrite_trap + 586 [0x2170bc] 4 ipc_mqueue_receive + 89 [0x211dc4] 4 thread_block + 33 [0x227654] 4 thread_block_reason + 309 [0x2275b0] 4 thread_go + 1961 [0x22698c] 4 thread_setrun + 1360 [0x225bba] 4 machine_idle + 239 [0x2ad0f5] 1 call_continuation + 28 [0x2a179c] 1 idle_thread + 58 [0x22812e] 1 thread_run + 118 [0x22743b] 1 thread_dispatch + 1347 [0x2270bc] 1 ml_set_interrupts_enabled + 47 [0x2a45e3] 1 lo_allintrs + 302 [0x2a1c2e] 1 interrupt + 182 [0x2ab419] 1 lapic_interrupt + 108 [0x2b32b2] 1 mp_kdp_exit + 860 [0x2b4506] 1 sync_iss_to_iks + 124 [0x2aabf6] Thread 84d623 User stack: 46 __semwait_signal + 10 (in libSystem.B.dylib) [0x7fff8760ef8a] Kernel stack: 46 semaphore_wait_continue + 0 [0x22a88f] }}}