xlc Compiler options to be used with debugger

While doing source code debugging, one generally compiles with -g option, and assumes that all compiler optimizations have been turned off. However, as far as the xlc compiler is concerned, this might not necessarily be true. With -g the compiler puts in line-number information and turns off some optimizations, but not all optimizations. To tell the compiler to turn off ALL optimizations, the -qnoopt option should be employed.

A few dbx quickies

Here are some of the dbx commands I frequently use to speed things up:

1. addcmd : Whenever I hit a breakpoint, I need to display the stack. I use addcmd to automatically display the stack when a breakpoint is hit.

2. set $repeat : I usually get tired of pressing 's' again and again while stepping through a program. I set this variable to automatically re-execute the last command when enter is pressed.

3. set -o vi : same as ksh's set -o vi

4. -E option : I often have to debug programs with MALLOC DEBUG exported. However, I don't want dbx itself to run with MALLOC DEBUG on. I invoke dbx as follows:
dbx -E MALLOCTYPE=debug -E MALLOCDEBUG=report_allocations,catch_overflow ./a.out

5. goto : Useful if I want to skip executing some code at times. Usually I do this if there is some user input to be read, or some sleep event, I just skip all that by using goto. Goto directly sets the instruction pointer.

I hope you find these tips useful. I'll put some more tips at some later point of time.