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From: seymour@milton.u.washington.edu (Richard Seymour)
Newsgroups: comp.lang.fortran
Subject: Re: Read dimension
Message-ID: <17228@milton.u.washington.edu>
Date: 27 Feb 91 01:56:09 GMT
References: <61477@eerie.acsu.Buffalo.EDU>
Organization: University of Washington, Seattle
Lines: 48

In article <61477@eerie.acsu.Buffalo.EDU> xiaofei@acsu.buffalo.edu (Xiaofei Wang) writes:
>main program 
>parameter(m=10,n=5)
>real a(m,n)
>call subroutine(a,b)
>end
>
... that he'd rather read in the array dimensions, rather than recompile
them.  As many others posted, there's no precise standard way, other than
dimensioning a monster array in the mainline, and then lying to the subroutine
and letting it view part of the original monster as the multi-dimensioned.
Thusly:
    main:       real x(1000000)
                read() i,j
                call subroutine(x,i,j)
                end
   sub:         subroutine subroutine(x,i,j)
                 dimension x(i,j)
                 ....
                 end
That's very portable.
A few people mentioned VAXes, but didn't give the VMS-answer: You CAN create
a virtual array on the fly.  You call the Create-Virtual-Space system 
service (SYS$CRETVA), giving it two addresses which define the size you
want.  It returns two virtual address, the first of which you pass to
your subroutine as the starting address (the (1,1) location) of your
array.
Roughly:  common/private/where    (i like to make private PSECTs)
          call make_space(where)
          end
           subroutine make_space(where)
          integer*4 want(2),result(2),access,size
          external sec$m_wrt
          integer*4 status,sys$cretva
          read()i,j
          size=i*j*4    (4 bytes per real datum)
          want(1)=%LOC(where)
          want(2)=want(1)+size    (number of bytes to create)
          access=%loc(sec$m_wrt)       (request write-access)
               status=SYS$CRETVA(want,result,access)
                call subroutine(%VAL(result(1)),i,j)
                end
                subroutine subroutine(a,i,j)
                dimension a(i,j)
                 ....
good luck
--dick
(reaching for his asbestos bvd's...)