GDB is a source-level debugger for compiled languages, primarily C and C++, although there is also support for a variety of other languages such as Go and Objective-C. You should read the notes for the version of GDB you are using to find out the current status of support for the various languages.
The project website is Debugging with GDB.
Out of the box, GDB has a command-line user interface, which some people find off-putting, although in reality, it is easy to use with a little practice. If command-line interfaces are not to your liking, there are plenty of front-end user interfaces to GDB, and I will describe three of them later.
