GNU Fortran has various special options that are used for debugging your program.
-fdebug-aux-vars ¶Renames internal variables created by the gfortran front end and makes
them accessible to a debugger. The name of the internal variables then
start with upper-case letters followed by an underscore. This option is
useful for debugging the compiler’s code generation together with
-fdump-tree-original and enabling debugging of the executable
program by using -g or -ggdb3.
-ffpe-trap=list ¶Specify a list of floating point exception traps to enable. On most
systems, if a floating point exception occurs and the trap for that
exception is enabled, a SIGFPE signal will be sent and the program
being aborted, producing a core file useful for debugging. list
is a (possibly empty) comma-separated list of either ‘none’ (to
clear the set of exceptions to be trapped), or of the following
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), ‘inexact’ (loss of precision
during operation), and ‘denormal’ (operation performed on a
denormal value). The first five exceptions correspond to the five
IEEE 754 exceptions, whereas the last one (‘denormal’) is not
part of the IEEE 754 standard but is available on some common
architectures such as x86.
The first three exceptions (‘invalid’, ‘zero’, and ‘overflow’) often indicate serious errors, and unless the program has provisions for dealing with these exceptions, enabling traps for these three exceptions is probably a good idea.
If the option is used more than once in the command line, the lists will
be joined: ’ffpe-trap=list1 ffpe-trap=list2’
is equivalent to ffpe-trap=list1,list2.
Note that once enabled an exception cannot be disabled (no negative form), except by clearing all traps by specifying ‘none’.
Many, if not most, floating point operations incur loss of precision
due to rounding, and hence the ffpe-trap=inexact is likely to
be uninteresting in practice.
By default no exception traps are enabled.
-ffpe-summary=list ¶Specify a list of floating-point exceptions, whose flag status is printed
to ERROR_UNIT when invoking STOP and ERROR STOP.
list can be either ‘none’, ‘all’ or a comma-separated list
of the following exceptions: ‘invalid’, ‘zero’, ‘overflow’,
‘underflow’, ‘inexact’ and ‘denormal’. (See
-ffpe-trap for a description of the exceptions.)
If the option is used more than once in the command line, only the last one will be used.
By default, a summary for all exceptions but ‘inexact’ is shown.
-fno-backtrace ¶When a serious runtime error is encountered or a deadly signal is
emitted (segmentation fault, illegal instruction, bus error,
floating-point exception, and the other POSIX signals that have the
action ‘core’), the Fortran runtime library tries to output a
backtrace of the error. -fno-backtrace disables the backtrace
generation. This option only has influence for compilation of the
Fortran main program.
See Options for Debugging Your Program or GCC in Using the GNU Compiler Collection (GCC), for more information on debugging options.