Ups is a X based source level debugger for the C, C++ and Fortran
programming languages.  It supports both run time debugging with
breakpoints and post-mortem debugging from a core file.  On Suns you can
attach ups to a running process. Ups runs in its own window, thus not
interfering with the target program's I/O.  The ups window has two major
areas - one showing a structured document representing the target state,
the other showing the source that is being executed.

Ups makes heavy use of direct manipulation and feedback.  When you add a
breakpoint it is shown as a pseudo C statement (#stop) in the source
display.  The current point of execution is highlighted in the source
display and you can watch it move as you step through loops and function
calls.  You can edit in fragments of interpreted C code (including
assignments to variables and calls to target functions).  There are
powerful facilities for exploring linked data structures - you can
recursively expand and collapse structures to follow links.

WWW:	http://ups.sourceforge.net/