VMS Mailbox I/O

Package of utilities to create,read/write, and close/delete of VMS mailbox devices.

Usage notes:

PRMMBX maxmsg bufquo logical_name
Defaults: PRMMBX 0 0 UA_PRMMBX , max. bufquo is 64K.
A user-mode mailbox device is created and the logical name assigned to it.

DELMBX mbx_device
mbx_device maybe a device specification like MBA100: or a the logical as in PRMMBX.
the specifies mailbox device is removed.

RDMBX mail_box_name [ dcl-symbol-to-return ] [Wait]
Reads a message from the specified mailbox device into a DCL symbol. (default symbol is MBXCMD).
RDMBX is immediate,nonblocking; With 3rd parameter=W it waits until a message is avalable in the mailbox.
DCL symbol is only set on successfull (>0 characters) mbx read. Check for $STATUS and use if f$type(mbxcmd) .nes. "" before use.

WRMBX mail_box_name text-of-message
writes a text message to the mailbox device. Write is immediate,nonblocking.

MBXEOF mail_box_name
Write EOF to a mailbox to terminate a pending MBX read with End_Of_File.

Program source files:

  1. PRMMBX
  2. RDMBX
  3. WRMBX
  4. MBXEOF
  5. DELMBX

To make the command available to DCL, either
$ symbol :== $location:exefile ,or
put symbol.exe into DCL$PATH, and use filename as command.


Joseph Huber , huber AT mppmuDOTmpgDOTde