When You Start
Debugging
The first time you debug a program, the debugger opens the
following windows:
- A Source window.
This window contains the source code (or disassembly
code, if the program was compiled without debug
information) for the main function of your program.
- The Session Control window. Use this window to
access other windows, to control the debugging of
threads and functions, and to
perform various debugger commands.
- When the program being
debugged (the "debuggee") is running
locally on Windows and OS/2,
the debugger also raises a Debug Application
window, which is a text-mode window. This window is a
text mode window, and is used for any console input and
output your program may require. For programs using a
graphical user interface (such as the User Interface
classes of IBM OpenClass), the Debug Application window
usually stays blank throughout the debugging session.
The debugger behavior at
startup depends upon the dominant language, as specified by the
CPP_DBG_LANG environment variable.
- CPP_DBG_LANG=CPP
- The debugger runs up to
the start of main. If you
checked the Debug program initialization check box
on the Startup dialog, the debugger starts at the
first line of disassembly code in your program. Use this
check box when you want to debug initialization code such
as the constructors for class objects declared at global
scope.
As you step through or run
your program, the debugger may raise additional Source windows
for other object files that are executed. If you exit the
debugger, then debug the same program later, these other windows
appear on reload, provided you saved program profile information.
When you start debugging a program for the first time, no breakpoints are set and no variables or
expressions are being monitored. During the debug session, you
may set breakpoints, or add variables
or expressions to a monitor. When you exit the debugger,
these breakpoints, variables and expressions are saved in the
program profile, and will be activated the next time you debug
this program