Menu
gdb allows one to catch exceptions when they're thrown, and when they're caught. But sometimes the line an exception is thrown has no symbols, or a breakpoint is triggered during exception handling. How do I inspect the value of the current exception?
548
To make the debugger catch all exceptions before any stack unwinding takes place, set a breakpoint on __raise_exception (see section Breakpoints, watchpoints, and catchpoints).
__cxa_throw. External interface to throw in the C++ support library. Takes three arguments: an exception object, a typeinfo for that object, and a pointer to the destructor to call when we are done with that object.
GDB catchpoints are a nice feature which allows you to intercept certain interesting things that your program might do. Most noticeably when a C++ exception is thrown, asserts, syscalls and signals.
You can see these breakpoints with the GDB maintenance command `maint info breakpoints' . Using the same format as `info breakpoints' , display both the breakpoints you've set explicitly, and those GDB is using for internal purposes. Internal breakpoints are shown with negative breakpoint numbers.
Earlier answers were correct when written (in 2013), but since then gdb and libstdc++ have changed.
libstdc++ now has some hooks that let gdb interact more nicely with the exception system. In particular, there is now enough information exposed for gdb to provide a $_exception convenience variable to the user. This variable holds the exception being thrown. It is only valid at exactly the spot where the exception is being caught; which you can stop at using catch catch.
See the page from the manual for details.
124
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
