One advantage of using MC-BBS is gaining access to people worldwide through the many forums from the Internet. Simon Coulter of IBM Australia, who participates in the Midrange forum (message area 74 on MC-BBS), is one such person. He recently answered a question about messaging for Neely Loring of South Carolina.
Loring asked, "I have written a CL program that deletes certain spooled files. The last command I send is a Send Program Message (SNDPGMMSG) with the TYPE(*STATUS) parameter. This program is run on the command line. When the program completes, I see the status message for only a split second before it disappears. How do I keep the message there for the user to see? This command could be run from any command line."
Coulter answered, "If the program worked, send the message as a completion (*COMP) message. If it failed, send it as an *ESCAPE message. You should have different messages defined for these, but I'd guess you are using CPF9898 (since you can't send impromptu messages as *STATUS messages)."
Coulter added an explanation of status messages. According to Coulter, "*STATUS messages are not what most people think. They are not used to inform a user or program of the final status, but are either a progress message or a message sent to a calling program saying, 'I had a problem. Do you care?'
"The first type is always coded as follows:
SNDPGMMSG MSGID(CPF9898) + MSGF(QCPFMSG) + MSGDTA('Building list. + Please wait ...) + TOPGMQ(*EXT) + MSGTYPE(*STATUS) "(You can change the MSGDTA or MSGID to anything you like.)
"The 'Query running' messages that OPNQRYF, Query Management, SQL, and Query/400 send out are of this form. The second type is more interesting. If you send a *STATUS message to the calling program and the program is monitoring for it (just like an *ESCAPE message), the sending program will end and the calling program will get control. If the calling program is not monitoring for messages (i.e., it doesn't care that the problem occurred), the sending program will continue processing and can handle the problem itself. This message is coded as follows:
SNDPGMMSG MSGID(CPF9898) + MSGF(QCPFMSG) + MSGDTA('Operation failed') + TOPGMQ(*PRV) MSGTYPE(*STATUS)
"These *STATUS messages can make some kinds of program-to-program communication very easy to code."
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- Ted Holt