This command creates a new subprocess and executes the specified image. When created, ATwish associates with it an identifier which triggers an event flag whenever the subprocess writes a record to standard output. When this event flag is set, ATwish will execute the procedure proc.
image should be a VMS executable, sepcified with the full file path. It
is possible to run a DCL shell, by specifying
SYS$SYSTEM:LOGINOUT.EXE.
proc expects three (3) arguments, namely the proc_id (process idenitifer), the "alive" flag and a string containing the returned output from the subprocess. The alive flag is 1 if the process is alive and 0 if it does not exist. Output is passed line at a time, so proc should be written with this in mind.
at_createproc returns the identifier of the subprocess created. This identifier may be used by other ATwish commands when referencing the subprocess (e.g. at_send).
Multiple subprocesses may be invoked, with each one reqiring a separate at_createproc command. Each subprocess may have its own parsing proc or may share a common one. Each subprocess used up a single event flag on the 0-31 local event flag pool. Other events will tap into this event flag pool as well (e.g. VMS, PGplot drivers, timer events etc.).