Hi Richard, thank you for your answer. I followed your advice and here is the output from gdb: gdb ./exam GNU gdb 6.1-20040303 (Apple version gdb-437) (Sun Dec 25 08:26:53 GMT 2005) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-apple-darwin"...Reading symbols for shared libraries .... done Function "cl_abort" not defined. (gdb) run Starting program: /usr/local/cln-1.1.11/tests/exam Reading symbols for shared libraries . done Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_INVALID_ADDRESS at address: 0x06a0afe1 0xa0b02584 in std::wclog () I attach the config.log Thanks, Christian