[Info-vax] Programming Languages (was: Re: VMS - The new file system. What do we know about it?...)

[Stephen Hoffman]

On 2016-11-14 00:23:14 +0000, Simon Clubley said:

> On a more serious note, I do hope that any new work to VMS is being 
> done purely in C at a minimum (with maybe even a better higher level 
> language for the userland code). I think the days of Bliss and 
> especially Macro-32 are long past for any new code (or at least for any 
> new source code files added to VMS from now on).

The shift from Macro32 or Bliss to C happened a couple of decades ago, 
within OpenVMS development.    There was a large project to allow the 
use of C for system programming, both for use within OpenVMS 
development and by customers.   That involved removing register-based 
calls and expunging dependencies on constructs such as co-routines from 
the external and many of the internal APIs.  Part of that project work 
included the move from the older VAX-ish "step 1" device drivers to the 
"step 2" device drivers and interfaces.  This project wasn't in the 
initial OpenVMS Alpha releases, but was in place and in use starting 
around OpenVMS V6.1; at the so-called "functional equivalence" release.

As for ~2021 to ~2026 and the future and as much as I like and use C 
for system-level development work, it has problems and issues.   
Locally deprecating specific calls from the standard library is a 
common start toward more reliable C code is a start, as are knobs such 
as QUESTCODE.   Tools for scanning C code for errors, vulnerabilities 
and for dependencies on undefined behavior are increasingly common 
practice too, both by the original authors of the code involved and 
also by folks looking for weaknesses in the code.

Accordingly, I'd be looking past C for system-level work.   Probably 
not to C++, though there are large system-level and application 
projects using (usually a subset of) C++ for development.   Definitely 
not to BASIC, Fortran or such, though those are fine choices for 
various applications.   Quite probably toward Rust for wholesale 
rewrites or wholly new system-level work, though that'd be a major 
shift for VSI and for OpenVMS end-users that might follow, and there 
are trade-offs there, too.  Rust avoids various of the worst of the 
holes within C, and Rust code is intended to interoperate with C 
libraries and frameworks.   There are some definite downsides to 
choosing Rust, not the least of which are its recent advent (such 
newness being major-scary for many organizations using OpenVMS), and 
that Rust isn't presently available on OpenVMS.   I would also look at 
Rust for application-level work, though there are other languages I'd 
consider there and that might be better choices than Rust and that are 
better choices than C, C++, BASIC and such.



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