[Info-vax] VAX BASIC global variables.

[Simon Clubley]

On 2021-10-15, Arne Vajhøj <arne at vajhoej.dk> wrote:
> On 10/15/2021 12:09 PM, E Thump wrote:
>> On Friday, October 15, 2021 at 4:44:49 PM UTC+1, Jeffrey H. Coffield
>> wrote:
>>> COMMON (MY_DATA) INTEGER a,b
>
>>> sub adder (integer c,integer d)
>
>> Next question to do with arrays. Instead of doing DIM Z(10) it seems
>> I should do COMMON (MY_DATA) INTEGER Z(10) and then use that exact
>> same line within the sub. The 10 and everything has to match. Am I on
>> the right lines there?
>
> Yes.
>
> Declarations *should* match.
>
> They are not strictly required to, but it becomes
> pretty messy if they don't.
>
> This does not look good:
>
> program hack
> common (mydata) long a(2)

Yuck. :-)

Common belongs back in the Fortran IV days. Please tell me that DEC Basic
supports user-defined record data types and that you can pass references
to instances of those data types around as subroutine parameters. :-)

> call s
> print a(0),a(1)
> end program
>
> sub s
> common (mydata) word a(4)
> a(0) = 1
> a(1) = 1
> a(2) = 2
> a(3) = 2
> end sub
>

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.