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

["sgk at troutmask dot apl.washington.edu" <gcc-bugzilla at gcc dot gnu dot org>]

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

--- Comment #7 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Tue, Nov 15, 2016 at 10:51:41PM +0000, kevin.b.beard at nasa dot gov wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78351
> 
> --- Comment #5 from Dr. Kevin B. Beard <kevin.b.beard at nasa dot gov> ---
> I've always understood that a comma will terminate a FORTRAN field - for
> example:
> 
> https://docs.oracle.com/cd/E19957-01/805-4939/z4000743a36d/index.html
> 
> Am I misunderstanding the F77 standard?

Yes.  If you read the text at the above URL, you find "The I/O system
is just being more lenient than described in the FORTRAN Standard."
The Fortran 77 standard contains

  13.2.1 Edit Descriptors

  An edit descriptor is either a repeatable edit descriptor or
  a nonrepeatable edit descriptor.

  The forms of a repeatable edit descriptor are:
    Iw
    Iw.m
  ...
  where:
    I, F, E, D, G, L, and A indicate the manner of editing

    w and e are nonzero, unsigned, integer constants

    d and m are unsigned integer constants

  13.5 Editing

  A field is a part of a record that is read on input or written
  on output when format control processes one I, F, E, D, G, L,
  A, H, or apostrophe edit descriptor.  The field width is the
  size in characters of the field.


  13.5.9 Numeric Editing

  The I, F, E, D, and G edit descriptors are used to specify
  input/output of integer, real, double precision, and complex
  data.

  The following general rules apply:

  (1) On input, leading blanks are not significant.  The
      interpretation of blanks, other than leading blanks, is
      determined by a combination of any BLANK= specifier and any
      BN or BZ blank control that is currently in effect for the
      unit (13.5.8). Plus signs may be omitted.  A field of all
      blanks is considered to be zero.

  (2) On input, with F, E, D, and G editing, a decimal point
      appearing in the input field overrides the portion of an edit
      descriptor that specifies the decimal point location. The input
      field may have more digits than the processor uses to approximate
      the value of the datum.

  (3) On output, ...

  (4) On output, ...

  (5) On output, ...

  13.5.9.1 Integer Editing

  The Iw and Iw.m edit descriptors indicate that the field to be
  edited occupies w positions.  The specified input/output list item
  must be of type integer. On input, the specified list item will
  become defined with an integer datum. On output, the specified list
  item must be defined with an integer datum.

  On input, an Iw.m edit descriptor is treated identically to an Iw
  edit descriptor.

  In the input field, the character string must be in the form of an
  optionally signed integer constant, except for the interpretation
  of blanks (13.5.9, item (1)).

I can find no place that states a comma delimits formatted input.

> Also, "-std=legacy" doesn't help.   It is difficult to modify
> many millions of lines of legacy code to change that.

I don't understand your point here.  -std=legacy would allow the
non-standard behaviour.  You would simply need to add -std=legacy
to your command line.  No modifications to the many millions of
lines of legacy code are required.

It seems that you're suggesting that gfortran should simply
implement Oracle's compiler behavior and silently accept the
non-standard input.  This is exactly how you got into your
current situation.  Instead of programming to the standard,
programmers wrote code accepted by whatever the compiler of
the dayi accepted.