[Info-vax] VAX BASIC global variables.

[E Thump]

On Friday, October 15, 2021 at 3:29:53 AM UTC+1, Stephen Hoffman wrote:
> On 2021-10-15 00:23:46 +0000, E Thump said: 
> 
> > Any VAX BASIC folk here?
> Really VAX BASIC, and not BASIC on OpenVMS VAX with the 
> DEC/Compaq/HP/HPE/VSI BASIC compiler? 
> 
> DEC/Compaq/HP/HPE/VSI BASIC replaced VAX BASIC a very long time ago 
> (back in VAX/VMS V3.x, IIRC)... 
> 
> Assuming this is not the archaic VAX BASIC compiler, but rather the 
> DEC/Compaq/HP/HPE BASIC compiler... 
> 
> https://vmssoftware.com/docs/VSI_BASIC_USER.pdf 
> https://vmssoftware.com/docs/VSI_BASIC_REF.pdf 
> 
> The keyword you're looking for is EXTERNAL. See page 105 in the 
> reference manual, linked above. 
> 
> COMMON (reference manual page 67) is not what you want. 
> 
> 
> -- 
> Pure Personal Opinion | HoffmanLabs LLC

It identifies as "VAX BASIC V3.8-000" when I start it. Came with my uVAX3100-80 running OpenVMS 6.2 

Here's what I've done now:

External SUB adder (integer,integer)
External INTEGER a,b

a=100
b=200

print "a+b before sub: ",a+b
call adder (10,20)
print "a+b after sub: ",a+b

end program

sub adder (integer c,integer d)
a=400
b=1000
print "a+b in sub: ",a+b
print "c+d in sub: ",c+d
end sub

compiles clean but throws this when linking :

%LINK-W-NUDFSYMS, 2 undefined symbols:
%LINK-I-UDFSYM,         A
%LINK-I-UDFSYM,         B
%LINK-W-USEUNDEF, undefined symbol A referenced
        in psect $CODE offset %X00000021
        in module TEST$MAIN file SYS$USERS:[ECKY]TEST.OBJ;24
%LINK-W-USEUNDEF, undefined symbol B referenced
        in psect $CODE offset %X0000002C
        in module TEST$MAIN file SYS$USERS:[ECKY]TEST.OBJ;24
%LINK-W-USEUNDEF, undefined symbol A referenced
        in psect $CODE offset %X00000048
        in module TEST$MAIN file SYS$USERS:[ECKY]TEST.OBJ;24
......