[RFC] [Ping] Comments on gfortran manual

[Dominique Dhumieres]

Daniel,

Thanks for the work on the manual. I only browse the patch and the texi is not
very friendly, but all what I have read so far is an improvement. So I think it
should be commited before 4.4.0 is released.

One part that could be extended is the one dealing with -fdefault-*-8 in the
light of the discussion in the thread -fdefault-integer-8 again!-(. 
In particular the comments from Steve Karg in http://gcc.gnu.org/ml/fortran/2008-12/msg00012.html:

These options are dangerous ... if the test
contains an EQUIVALENCE or COMMON with mixed REAL and INTEGER
variables, you cannot use -fdefault-real-8 without also using
-fdefault-integer-8.  There is also an issue with the effect of
these options on ISO C Binding.

Also

 @opindex @code{fdefault-double-8}
 Set the @code{DOUBLE PRECISION} type to an 8 byte wide type.
+@c XXX: Isn't this "always" the case?  Does this affect KIND(1.d0)?

It is not my reading of this option. If I am not mistaken, it sets all
default REAL to an 8 byte wide type. I am not sure of what it does to
things such that sin(1.0). Some compilers have a different option for
constants and variables.

Dominique