Hey, > I am trying debug gcc 4.5.0 use gdb on ubuntu > > and encounter the problem by seeing "value optimized out". as fellow: Did you get this behavior even with the -O0 GCC build? Basically, GDB tells you what's wrong with the executable. For a short explanation, check this page (http://www.cs.utk.edu/~vose/c-stuff/onlinedocs/gdb_7.html) and search for "value optimized out". I made the experience that using -O0 shouldn't produce the "value optimized out" problem, because the code is not optimized. Andi
