The purpose of a debugger such as GDB is to allow you to see what is
going on "inside" another program while it executes, or what another
program was doing at the moment it crashed.

GDB can do four main kinds of things (plus other things in support of
these) to help you catch bugs in the act: (1) start your program,
specifying anything that might affect its behavior, (2) make your
program stop on specified conditions, (3) examine what has happened,
when your program has stopped, (4) change things in your program, so
you can experiment with correcting the effects of one bug and go on to
learn about another.

You can use GDB to debug programs written in C, C++, and Modula-2.
Fortran support will be added when a GNU Fortran compiler is ready.

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