UW AMath High Performance Scientific Computing
AMath 483/583 Class Notes
Spring Quarter, 2011

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Debugging and debuggers

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Fortran Software Packages

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Fortran debugging

For some general tips on writing and debugging programs in any language, see Debugging and debuggers.

Compiling with various gfortran flags

There are a number of flags you can use when compiling your code that will make it easier to debug.

Here’s a generic set of options you might try:

$ gfortran -g -W -Wall -fbounds-check -pedantic-errors \
      -ffpe-trap=zero,invalid,overflow,underflow  program.f90

See Useful gfortran flags for more information. Most of these options indicate that the program should give warnings or die if certain bad things happen.

Compiling with the -g flag indicates that information should be generated and saved during compilation that can be used to help debug the code using a debugger such as gdb or totalview. You generally have to compile with this option to use a debugger.

The gdb debugger

This is the Gnu open source debugger for Gnu compilers such as gfortran. Unfortunately it works very poorly for Fortran.


Totalview is a commercial debugger that works quite well on Fortran codes together with various compilers, including gfortran. It also works with other languages, and for parallel computing.

See Rogue Wave Softare – totalview family.