GDB

GDB is the debugger of the GNU Project

Developer: GNU Platforms: (all systems) Category: Debugger License: GPL Website: GDB homepage

The GNU debugger (GDB) can be used to inspect problems in programs. It allows to trace and alter the execution of running programs as well as to create and inspect coredumps.

Usage

The gdb debugger is available on HLRS systems without the need to load a module.

Note: Do not forget to compile your application with debugging info (-g option).

Obtaining coredumps of crashing programs

GDB can be used to obtain a coredump of a program crash. To do so start gdb with the program and its arguments

$ gdb --args <program> <program args>

Then start program execution and run until it crashes. When the program crashed save a corefile of the crashed process via the generate-core-file command - optionally providing an output file name:

(gdb) run
(gdb) generate-core-file [file]

Obtaining a backtrace of a crashing MPI program

To get a backtrace of a crashing program start it via gdb as follows:

mpirun -n 2 gdb -batch -ex "run" -ex "bt" <program>

Note: To get the rank of the crashing process for Open MPI the --tag-output option can be used.

HAWK/MPT special

To use gdb with MPT on HAWK one has to run with MPI_SHEPHERD=true and provide the absolute path to gdb:

MPI_SHEPHERD=true mpirun -n 2 $(which gdb) <program>

See also

• Software Development Tools, Compilers & Libraries

External links

• GDB homepage