Debugging

Use truss to trace system calls
$ truss ./a.out
Many advanced options to truss
-t, -a, -e, -v, -r, -w
See truss(1)
Dynamic library tracing
LD_TRACE environment variable
Not currently supported with libthread
Memory debugging
MALLOC_CHECKS environment variable
MALLOC_STATS environment variable
See malloc(3C)
Source debugging
debug, jdb, gdb
Documentation
SCOhelp, man command, http://doc.sco.com