Hi, Standard versions of GCC don't define __unused. And LLVM/GCC doesn't define __block anymore. I don't know whether it is right to put it in testing/dispatch_test.h, but it at least affects all test applications at once. Together with the other patches I sent the last days, this is everything required to compile and use libdispatch on Linux (with the exception of queue_finalizer due to arc4random). ciao, Mario Index: testing/dispatch_test.h =================================================================== --- testing/dispatch_test.h (Revision 171) +++ testing/dispatch_test.h (Arbeitskopie) @@ -1,5 +1,18 @@ #include <errno.h> +/* standard GCC and LLVM/GCC don't define __unused by default */ +#ifndef __unused + #define __unused __attribute__((__unused__)) +#endif + +/* standard LLVM/GCC doesn't define __block by default, because + * used as a parameter name in include/c++/4.2.1/ext/mt_allocator.h as well */ +#if __BLOCKS__ + #ifndef __block + #define __block __attribute__((__blocks__(byref))) + #endif +#endif + __BEGIN_DECLS void test_start(const char* desc);