Re: READ ( UNIT = TRIM(String),...

[Philippe Schaffnit <P dot Schaffnit at access dot rwth-aachen dot de>]

Hi!

Thanks a lot for the explanations.

Sorry about the noise...

Philippe

Jerry DeLisle wrote:
> 
> Philippe Schaffnit wrote:
> > Hi!
> >
> > I was trying to iron out a wrinkle from a piece of code, when I stumbled
> > onto something which I find quite surprising, what I hold to be a
> > 'reject valid' from GFortran: the 'reject valid' would belong here, the
> > other bit probably not, but if a kind soul could nevertheless enlighten
> > me, I would greatly appreciate it!
> >
> > Take the following piece of code:
> >
> > !
> >       PROGRAM Test
> > !
> >       IMPLICIT NONE
> > !
> >       INTEGER                 ::   Number, IO_Stat
> > !      CHARACTER ( LEN = 250 ) ::   String = "Hello world!"
> >       CHARACTER ( LEN = 250 ) ::   String = "/Hello world!"
> > !
> > !      READ ( UNIT = TRIM(String), FMT = *, IOSTAT = IO_Stat ) Number
> >       READ ( UNIT = String, FMT = *, IOSTAT = IO_Stat ) Number
> >       WRITE ( UNIT = 6, FMT = * ) Number, IO_Stat
> > !
> >       END PROGRAM Test
> > !
> >
> > The obvious one first: "GNU Fortran (GCC) 4.3.0 20071026 (experimental)
> > [trunk revision 129646]" rejects "READ ( UNIT = TRIM(String)," with
> >
> > READ ( UNIT = TRIM(String), FMT = *, IOSTAT = IO_Stat ) Number
> >                   1
> > Error: UNIT specification at (1) must be an INTEGER expression or a
> > CHARACTER variable
> >
> > Is this warranted by the standard?, I would expect it to be fine: the
> > SGI, Lahey and Sun compilers seem happy with it... (for the record, the
> > Intel one doesn't either)
> >
> > Now for the really weird part, if I remove the 'TRIM' to get over this,
> > I would expect an IO error to be raised, but I have yet to find a
> > compiler which does!
> >
> The slash is considered a value separator. The value is read until a separator
> is found.  Right from the standard, 10.8:
> 
>   A value separator is
> 
> (1)   A comma optionally preceded by one or more contiguous blanks and
> optionally followed by one or more contiguous blanks,
> 
> (2) A slash optionally preceded by one or more contiguous blanks and optionally
> followed by one or more contiguous blanks, or
> 
> (3) One or more contiguous blanks between two nonblank values or following the
> last nonblank value, where a nonblank value is a constant, an râ^-c form, or an r
> form.
> 
> If you try to read a second value in that READ statement you will get the
> expected error.
> 
>        CHARACTER ( LEN = 250 ) ::   String = "/Hello world!"
> 
>        READ ( UNIT = String, FMT = *, IOSTAT = IO_Stat ) Number, number
> 
> Regards,
> 
> Jerry