[Bug fortran/78351] comma not terminating READ of formatted input field - ok in 4.1.7, not 4.4.7- maybe related to 25419?

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78351

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
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                 CC|                            |kargl at gcc dot gnu.org

--- Comment #3 from kargl at gcc dot gnu.org ---
(In reply to Dr. Kevin B. Beard from comment #0)
> Created attachment 40038 [details]
> Simple example - comma no longer  a format field delimiter - gfortran 4.1.2
> ok, 4.4.7- fails
> 
> Here @ NASA we often have strings to read of the form:
> 
> #,#,#,#,.....
> 
> and on many platforms, gfortran 4.1.2 and (most?) earlier, Intel Fortran
> 16.0.3, g77-3.4.6 and most other FORTRANs, it would treat the "," as a field
> delimiter during a formatted READ - for example (x1.f):
> 
>       character*80 s
>       s= '1,2,3,,,,'
>       READ(s,'(2i10)') i,j
>       write(6,'(2i10)') i,j
>       end
> 
> would print "       1         2".
> 
> However, 4.4.7 ("gfortran -o x1 x1.f") now (11/2016) fails with 
> 
> "Fortran runtime error: Bad value during integer read".
> 
> I believe it worked with 4.4.7 back in 9/2016 on ScientificLinux-6.4 fine,
> but there have been security patches done since then.  It also fails on
> 4.8.5 and 5.3.0 under Red Hat Enterprise Linux Server release 5.11  It would
> be very nice to be able to restore the old behavior.
> 
> This may be related to bug#25519.

gfortran's behavior conforms to the standard while your code
does not conform.  Perhaps, gfortran should accept a comma as
a field delimiter under -std=legacy, but preference should
be to fixing the wrong code.

  10.7.2.2 Integer editing

  The Iw and Iw.m edit descriptors indicate that the field to be
  edited occupies w positions, except when w is zero.  When w is
  zero, the processor selects the field width.  On input, w shall
  not be zero.  The specified input/output list item shall be of
  type integer. ...

  On input, m has no effect.

  In the input field for the I edit descriptor, the character string
  shall be a signed-digit-string (R409), except for the interpretation
  of blanks.

  R409 signed-digit-string  is [ sign ] digit-string
  R410 digit-string
  R411 sign                 is digit [ digit ] ...

                            is +
                            or ­


Perhaps, you want list-directed formatting

  10.10 List-directed formatting

  10.10.1 General

  List-directed input/output allows data editing according to the type
  of the list item instead of by a format specification.  It also allows
  data to be free-field, that is, separated by commas (or semicolons) or
  blanks.