[Info-vax] CRTL and RMS vs SSIO

[John Dallman]

In article <44512ead-b6e0-4735-b63b-0db699f8b978n at googlegroups.com>,
lawrencedo99 at gmail.com (Lawrence D_Oliveiro) wrote:
> On Saturday, October 16, 2021 at 10:03:36 AM UTC+13, Stephen 
> Hoffman wrote:
> > Linux shimulation is not going to speed the delivery of the 
> > OpenVMS x86-64 semi-production and production versions, nor the 
> > availability of native compilers. 
> 
> If VMS compatibility for user-mode code just takes the form of a 
> library to link against, then VMS-specific compilers shouldn_t be 
> necessary. You could use the existing GNU and LLVM compilers, and 
> just implement wrappers that understand the VMS-specific options.

Won't work without ludicrous amounts of effort. There are subtle, but
pervasive, differences in the process model, the i/o model, the error
handling, and many other aspects of programming for the two operating
systems. That's why the Unix-emulation products for VMS have failed, and
why there are still VMS customers - it's been too hard for them to move
applications to other platforms, for a variety of reasons. The ones that
were easy to move have largely been done. What's left is the ones that
are difficult. 

The reasons for wanting to use the DEC compiler front-ends is that DEC
languages weren't terribly standards-conformant: once upon a time, the
DEC market was big enough that the company didn't worry too much about
those things. It isn't just additional command-line options, it's
differences in the languages and libraries. Providing Clang for C++ and
standard-conformant C is an addition: the DEC C will still be needed for
historical code. 

John