How do I get the value and type of the current exception in C++ using gdb?

c++ debugging exception gdb inspection
Matt Joiner picture Matt Joiner · May 1, 2013 · Viewed 12.4k times · Source

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?

Answer

Tom Tromey picture Tom Tromey · Oct 20, 2015

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.

Related questions

Eclipse-CDT: How do I configure the debugger to stop on an exception?

This might be a GDB question.. but I'd like to run my app in the debugger and have the debugger break when an exception is thrown, so I can see where the code is and what its doing at that …

Read More
wntdll.pdb not loaded - Can't see the exception

Sometimes when I quit my application (SaviHOST running a DLL that I'm making) I show this screen: Unfortunately I don't know where the error happens, because it just load that screen, not the line where the exception is made. How …

Read More
Debugging with command-line parameters in Visual Studio

I'm developing a C++ command-line application in Visual Studio and need to debug it with command-line arguments. At the moment I just run the generated EXE file with the arguments I need (like this program.exe -file.txt) , but this …

Read More