[Info-vax] GCC for VMS, was: Re: fortran compiler roadmap?

[Johnny Billquist]

On 2013-04-23 17:23, Bob Koehler wrote:
> In article <kl4ag3$29k$1 at speranza.aioe.org>, glen herrmannsfeldt <gah at ugcs.caltech.edu> writes:
>>
>> It seems to have taken a special fixup in the VMS linker to make it work.
>
>     For passing CHARACTER to CHARACTER, no fix up is needed.  Lots of
>     Fortran-77 compilers only support that.  To implement the
>     Fortran-77 standard the compiler needs to pass both the size and
>     location of CHARACTER arguments.
>
>     But DEC supported passing character constants to integer, real, ...
>     variables, as we had always done in Fortran-IV.  That took a linker
>     fixup as in the calling routine the compiler would generate pass by
>     descriptor, but in the receiving routine it would be expecting pass
>     by reference.
>
>     Different Fortran compilers have different ways of passing CHARACTER
>     variable length between routines, but the RSX just didn't pass it.
>     So existing RSX code that passed character constants to integer, ...
>     would keep running, but new code could not take advantage of the
>     passed length wihtout explicitly passing it.

You just do what you always did, you passed the length as a separate 
parameter. (In PDP-11 F77 that is.)

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
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