Debugging with GDB (February 2008)

14 Debugging with GDB
-cd directory
Run GDB using directory as its working directory, instead of the current direc-
tory.
-dbx Support additional dbx commands, including:
• use
• status (in dbx mode, status has a different meaning than in default GDB
mode.)
• whereis
• func
• file
• assign
• call
• stop
-fullname
-f gnu Emacs sets this option when it runs GDB as a subprocess. It tells GDB to
output the full file name and line number in a standard, recognizable fashion
each time a stack frame is displayed (which includes each time your program
stops). This recognizable format looks like two ‘\032’ characters, followed by
the file name, line number and character position separated by colons, and a
newline. The Emacs-to-GDB interface program uses the two ‘\032’ characters
as a signal to display the source code for the frame.
-epoch The Epoch Emacs-GDB interface sets this option when it runs GDB as a sub-
process. It tells GDB to modify its print routines so as to allow Epoch to
display values of expressions in a separate window.
-annotate level
This option sets the annotation level inside GDB. Its effect is identical to using
‘set annotate level ’ (see Chapter 20 [Annotations], page 261). Annotation
level controls how much information does GDB print together with its prompt,
values of expressions, source lines, and other types of output. Level 0 is the
normal, level 1 is for use when GDB is run as a subprocess of gnu Emacs, level
2 is the maximum annotation suitable for programs that control GDB.
-async Use the asynchronous event loop for the command-line interface. GDB pro-
cesses all events, such as user keyboard input, via a special event loop. This
allows GDB to accept and process user commands in parallel with the debugged
process being run
1
, so you don’t need to wait for control to return to GDB be-
fore you type the next command. (Note: as of version 5.0, the target side of
the asynchronous operation is not yet in place, so ‘-async’ does not work fully
yet.)
When the standard input is connected to a terminal device, GDB uses the
asynchronous event loop by default, unless disabled by the ‘-noasync’ option.
1
GDB built with djgpp tools for MS-DOS/MS-Windows supports this mode of operation, but the event
loop is suspended when the debug target runs.