2.5 Options for debugging your program or GNU Fortran

GNU Fortran has various special options that are used for debugging either your program or the GNU Fortran compiler.

-fdump-fortran-original

Output the internal parse tree after translating the source program into internal representation. Only really useful for debugging the GNU Fortran compiler itself.

-fdump-optimized-tree

Output the parse tree after front-end optimization. Only really useful for debugging the GNU Fortran compiler itself.

Output the internal parse tree after translating the source program into internal representation. Only really useful for debugging the GNU Fortran compiler itself. This option is deprecated; use -fdump-fortran-original instead.

-ffpe-trap=list

Specify a list of IEEE exceptions when a Floating Point Exception (FPE) should be raised. On most systems, this will result in a SIGFPE signal being sent and the program being interrupted, producing a core file useful for debugging. list is a (possibly empty) comma-separated list of the following IEEE exceptions: ‘invalid’ (invalid floating point operation, such as SQRT(-1.0)), ‘zero’ (division by zero), ‘overflow’ (overflow in a floating point operation), ‘underflow’ (underflow in a floating point operation), ‘precision’ (loss of precision during operation) and ‘denormal’ (operation produced a denormal value).

Some of the routines in the Fortran runtime library, like ‘CPU_TIME’, are likely to trigger floating point exceptions when ffpe-trap=precision is used. For this reason, the use of ffpe-trap=precision is not recommended.

-fbacktrace

Specify that, when a runtime error is encountered or a deadly signal is emitted (segmentation fault, illegal instruction, bus error or floating-point exception), the Fortran runtime library should output a backtrace of the error. This option only has influence for compilation of the Fortran main program.

-fdump-core

Request that a core-dump file is written to disk when a runtime error is encountered on systems that support core dumps. This option is only effective for the compilation of the Fortran main program.

See Options for Debugging Your Program or GCC, for more information on debugging options.