HP gnu source-level debugger 5992-4701 manual Setting catchpoints

GDB itself sometimes sets breakpoints in your program for special purposes, such as proper handling of longjmp (in C programs). These internal breakpoints are assigned negative numbers, starting with -1; 'info breakpoints' does not display them.

You can see these breakpoints with the GDB maintenance command 'maint info breakpoints'.

maint info breakpoints Using the same format as 'info breakpoints', display both the breakpoints you have set explicitly, and those GDB is using for internal purposes. Internal breakpoints are shown with negative breakpoint numbers. The type column identifies what kind of breakpoint is shown:

breakpoint	Normal, explicitly set
	breakpoint.
watchpoint	Normal, explicitly set
	watchpoint.
longjmp	Internal breakpoint, used to
	handle correctly stepping
	through longjmp calls.
longjmp resume	Internal breakpoint at the
	target of a longjmp.
until	Temporary internal
	breakpoint used by the GDB
	until command.
finish	Temporary internal
	breakpoint used by the GDB
	finish command.
shlib events	Shared library events.

5.1.2 Setting catchpoints

You can use catchpoints to cause the debugger to stop for certain kinds of program events, such as C++ exceptions or the loading of a shared library. Use the catch command to set a catchpoint.

catch event Stop when event occurs. event can be any of the following:

throw	The throwing of a C++ exception.
catch	The catching of a C++ exception.
exec	A call to exec. This is currently only
	available for HP-UX.
fork	A call to fork. This is currently only
	available for HP-UX.

56 Stopping and Continuing