Dear Alberto:
Alberto Fasso' wrote:
> Some people have mentioned INQUIRE.
>
> I have a program which takes its input from a number of files. These may
> have been written either as formatted or unformatted (binary) but contain
> essentially the same kind of information.
>
> Therefore I need a way to tell the program how each file should be read. I
> have tried INQUIRE with the FORMATTED=fmt option, but it is completely
> useless. Indeed, although the fmt variable is supposed to take the values
> 'YES' or 'NO', it looks that the standard allows also the response
> 'UNKNOWN'. And this is the value which I find systematically returned.
>
> What is the point of providing such a facility, if it cannot be used?
>
> Alberto Fasso'
>
> --------------------------------------------------
> Alberto Fasso'
> Stanford Linear Accelerator Center
> Radiation Physics Dept. ms 48
> 2575 Sand Hill Road
> Menlo Park, CA 94025
>
> Tel. (1 650) 926 4062 Fax: (1 650) 926 3569
Yes, the Fortran 95 standard required that UNKNOWN is one of the valid
values which INQUIRE (FORMATTED=scalar-default-char-variable) may return.
Here is the text from the F95 standard:
[Begin F95 text]
9.6.1.11 FORMATTED= specifier in the INQUIRE statement
The scalar-default-char-variable in the FORMATTED= specifier is assigned the
value YES if FORMATTED is included in the set of allowed forms for the file,
NO if FORMATTED is not included in the set of allowed forms for the file, and
UNKNOWN if the processor is unable to determine whether or not FORMATTED is
included in the set of allowed forms for the file.
[End of F95 text]
Whether a Fortran compiler can determine if formatted I/O is allowed under
a given set of circumstances is highly variable from one processor to the
next. It depends on the OS, the file system, the run time library and the
quality of the comiler implementation. Under many, if not most, OSes the file
system does not keep track of whether the file's contents is formatted or
unformatted. Hence, the set of circumstances in which the procesor can
determine whether or not formatted I/O is allowed may be quite small.
Why have such a facility? Well, in some cases, the compiler can make this
determination. In those cases, this information is quite useful.
The best approach in your case is to take a sample of records and find out
what percentage of the characters are non-printable characters and what
percentage are printable. Unless the percentage of printable characters is
quite high, most likely the data is unformatted.
--
----------
Sincerely,
Craig T. Dedo Internet:
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