Re: remark on defining size of basic types

On 05.04.2024 02:46, Lawrence D'Oliveiro wrote:

On Fri, 5 Apr 2024 02:25:22 +0200, Janis Papanagnou wrote:
 

On 05.04.2024 01:38, Lawrence D'Oliveiro wrote:
>

On Thu, 4 Apr 2024 15:15:26 +0200, Janis Papanagnou wrote:
>

Sometimes it's useful to have an unbounded or parameterized integral
data type available ...

>
Interestingly, Fortran (of all things) has that.

>
Was that the e.g. '*8' syntax? - Did it allow arbitrary lengths?

 
No, and no. Since Fortran 2003, [...]

For the first question I thought you were referring to old Fortran
versions - I certainly was referring to that syntax, and I see that
my memories were correct -, where you can find types like INTEGER*1,
INTEGER*2, INTEGER*5, INTEGER*8 (see e.g. [*], Table 11 on page 17).

[*] https://docs.nvidia.com/hpc-sdk/pgi-compilers/17.9/pdf/pgi17fortref.pdf

you can parameterize a custom type
definition with integer values. These can be used to specify the sizes of
arrays, or they can be used as codes for the different (implementation-
defined) precisions of integer and real types. An example from the
language spec:
 
    TYPE :: t1(k1,k2)
        INTEGER, KIND :: k1,k2
        REAL(k1) a(k2)
    END TYPE
 
This defines a custom type “t1”, which is an array of reals; the first
parameter determines the precision of the reals, and the second one
specifies the length of the array.
 
There are various query mechanisms (built-in functions, standard modules)
to determine the valid values of the number-precision codes.

Yes, but I read that 'KIND' specification as a readable variant
of the old syntax where you can also just select between a couple
standard sizes for integers (like SHORT, LONG, etc.).

(But I'm not much interested in Fortran, and we're off-topic.)

Janis