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Puhti and Mahti are being decommissioned in stages, and their storage areas will become fully unavailable from 15 October 2026. Clean up unnecessary files and move any data you need to keep by 31 August 2026. See the Roihu data migration guide for instructions on transferring your data to Roihu.

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gdb: GNU Debugger

Available

  • Puhti
  • Mahti
  • Roihu-CPU

License

Usage is possible for both academic and commercial purposes.

Usage

GNU Debugger (GDB) can be used to debug compiled programs (written in C, C++, Fortran). It can perform four main tasks: inform about everything that might affect the behavior, make the program stop in specific conditions, examine why the program stopped, and finally change things in the program in order to correct the effects of a bug.

In order to use the debugger the program has to be compiled with -g flag to enable symbolic debugging.

One can either start the application under the debugger, or attach the debugger to a running application.

In order to start the application under the debugger, launch first an interactive session and execute then: 

gdb --tui ./myexecutable

In order to attach to a running application, connect first to a compute node. Next, you need to find the process ID <pid> e.g. by running the command ps ux, attach then debugger to that: 

gdb --tui ./myexecutable <pid>

If additional arguments are needed for the program, one can use the option --args before the name of the executable. The --tui option starts a nice terminal interface that shows the source code.

In the gdb prompt it is possible to enter commands such as break, step, or run. For more information check the official page: GDB.