[Info-vax] Learning VMS application programming

[JF Mezei]

A couple of comments:

VMS is not that different from other OS when you do stuff like
accounting (read files, produce reports). You need to learn to write
your report to a file and then print the file. There are tricks where
you application can write the report and have the file spooled to print
automatically.

There are a few subtilities. To exit a program "cleanly" in C, you
exit(1)  (exit code of 1 is "success").

If you need to have 2 processes talk to each other, there are many ways.
The easiest is to use a mailbox device.

SYS$CREMBX , followed by SYS$ASSIGN followed by SYS$QIO to do IOs and
SYS$DASSGN

(help system <name of service) gets you some documentationl or get the
full doc at the manual on system services.

For process 2 to know what mailbox device was create by process 1,
process 1 might create it with a "goup" logical name which becomes
visible to process 2 if it is in the same IIC group (thing user groups
in unix).

Once you know what system services you need to use, the documentation is
very complete. There is/was a introduction to VMS programming which
provided a whole lot of details on the various services offered by the
opetating system.