Hi all. I am tying to compile the SOP_Flatten example in a Mac Os X Leopard using hcustom. I got these errors: Making SOP_Flatten.o and /Users/pablo/Library/Preferences/houdini/11.0/dso/SOP_Flatten.dylib from SOP_Flatten.C cc1plus: warning: command line option "-fobjc-gc-only" is valid for ObjC/ObjC++ but not for C++ /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h: In function ‘int32 SYS_AtomicImpl::test_and_add(int32*, int)’: /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:345: error: ‘__sync_fetch_and_add’ was not declared in this scope /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h: In function ‘int32 SYS_AtomicImpl::compare_and_swap(int32*, int32, int32)’: /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:351: error: ‘__sync_val_compare_and_swap’ was not declared in this scope /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h: In function ‘int64 SYS_AtomicImpl::test_and_set64(int64*, int64)’: /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:358: error: ‘__sync_lock_test_and_set’ was not declared in this scope /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h: In function ‘int64 SYS_AtomicImpl::test_and_add64(int64*, int64)’: /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:365: error: ‘__sync_fetch_and_add’ was not declared in this scope /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h: In function ‘int64 SYS_AtomicImpl::compare_and_swap64(int64*, int64, int64)’: /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:372: error: ‘__sync_val_compare_and_swap’ was not declared in this scope /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h: In function ‘void SYS_AtomicImpl::store(int32*, int32, SYS_MemoryOrder)’: /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:389: error: ‘__sync_synchronize’ was not declared in this scope /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:399: error: ‘__sync_lock_release’ was not declared in this scope /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:405: error: ‘__sync_lock_test_and_set’ was not declared in this scope /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h: In function ‘int32 SYS_AtomicImpl::load(const int32*, SYS_MemoryOrder)’: /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:428: error: ‘__sync_synchronize’ was not declared in this scope /Library/Frameworks/Houdini.framework/Resources/toolkit/include/SYS/SYS_AtomicImpl.h:435: error: ‘__sync_val_compare_and_swap’ was not declared in this scope Compile failed I have Xcode but not sure if it is the latet version because seems I don´t have gcc-4.2 in my systems just 4.0.1. I have also tried to compile using Makefiles, with the Makefile by Sebastian Schmidt: http://www.sschmidt.subsites.org/484.0.html But same result, Any ideas? Thanks