Some languages, such as GNU C++, implement exception handling. You can use GDB to examine what caused your program to raise an exception, and to list the exceptions your program is prepared to handle at a given point in time.
catchcommand. exceptions is a list of names of exceptions to catch.
You can use
info catch to list active exception handlers.
See section Information about a frame.
There are currently some limitations to exception handling in GDB:
catch is not the best way to debug exception handling:
if you need to know exactly where an exception is raised, it is better to
stop before the exception handler is called, since that way you
can see the stack before any unwinding takes place. If you set a
breakpoint in an exception handler instead, it may not be easy to find
out where the exception was raised.
To stop just before an exception handler is called, you need some
knowledge of the implementation. In the case of GNU C++, exceptions are
raised by calling a library function named
which has the following ANSI C interface:
/* addr is where the exception identifier is stored. ID is the exception identifier. */ void __raise_exception (void **addr, void *id);
To make the debugger catch all exceptions before any stack
unwinding takes place, set a breakpoint on
(see section Breakpoints, watchpoints, and exceptions).
With a conditional breakpoint (see section Break conditions) that depends on the value of id, you can stop your program when a specific exception is raised. You can use multiple conditional breakpoints to stop your program when any of a number of exceptions are raised.
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