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<h3 class="section">2.5 Options for debugging your program or GNU Fortran</h3>
<p><a name="index-options_002c-debugging-174"></a><a name="index-debugging-information-options-175"></a>
GNU Fortran has various special options that are used for debugging
either your program or the GNU Fortran compiler.
<dl>
<dt><code>-fdump-fortran-original</code><dd><a name="index-g_t_0040code_007bfdump_002dfortran_002doriginal_007d-176"></a>Output the internal parse tree after translating the source program
into internal representation. Only really useful for debugging the
GNU Fortran compiler itself.
<br><dt><code>-fdump-optimized-tree</code><dd><a name="index-g_t_0040code_007bfdump_002dfortran_002doptimized_007d-177"></a>Output the parse tree after front-end optimization. Only really
useful for debugging the GNU Fortran compiler itself.
<p><a name="index-g_t_0040code_007bfdump_002dparse_002dtree_007d-178"></a>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
<code>-fdump-fortran-original</code> instead.
<br><dt><code>-ffpe-trap=</code><var>list</var><dd><a name="index-g_t_0040code_007bffpe_002dtrap_003d_007d_0040var_007blist_007d-179"></a>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. <var>list</var> is a (possibly empty) comma-separated
list of the following IEEE exceptions: ‘<samp><span class="samp">invalid</span></samp>’ (invalid floating
point operation, such as <code>SQRT(-1.0)</code>), ‘<samp><span class="samp">zero</span></samp>’ (division by
zero), ‘<samp><span class="samp">overflow</span></samp>’ (overflow in a floating point operation),
‘<samp><span class="samp">underflow</span></samp>’ (underflow in a floating point operation),
‘<samp><span class="samp">precision</span></samp>’ (loss of precision during operation) and ‘<samp><span class="samp">denormal</span></samp>’
(operation produced a denormal value).
<p>Some of the routines in the Fortran runtime library, like
‘<samp><span class="samp">CPU_TIME</span></samp>’, are likely to trigger floating point exceptions when
<code>ffpe-trap=precision</code> is used. For this reason, the use of
<code>ffpe-trap=precision</code> is not recommended.
<br><dt><code>-fbacktrace</code><dd><a name="index-g_t_0040code_007bfbacktrace_007d-180"></a><a name="index-backtrace-181"></a><a name="index-trace-182"></a>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.
<br><dt><code>-fdump-core</code><dd><a name="index-core_002c-dump-183"></a><a name="index-g_t_0040code_007bfdump_002dcore_007d-184"></a>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.
</dl>
<p>See <a href="../gcc/Debugging-Options.html#Debugging-Options">Options for Debugging Your Program or GCC</a>, for more information on
debugging options.
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