>>33

Most C/C++ compilers that implement some kind of tail-call optimization (TCO) will refuse to do it for a large number of cases, including some of these:

• Taking the address-of a stack allocated variable (using &)
• If you use alloca() (or a C99-variable-sized array)
• If you use setjmp() or exceptions
• If you're using Visual C/C++ version 8.1 or earlier
• If your tail call crosses a module boundary
• If the number of arguments changes (sometimes!)
• If it's an indirect function call
• If any of the types change the ABI needed (int->float, etc)

It's funny: The same people who worry about stack smashing are the same people who try and recover when malloc() returns NULL.