Mapping Program Status Data Structures
The PSDS can be used to create exception management in a program.
IBM offers a mechanism for RPG application program to access system information available to the program. The program status data structure (PSDS) can be defined, allowing the program view and manage exception/error information. The PSDS has been limited to the main source section of the application; therefore, there is only one PSDS per module.
Externally Defined PSDS
A simple way of defining a data structure is to reference an external file description. The DDS below describes the fields of the PSDS for use in any RPG program. Making a map of the PSDS standardizes defining the DS subfields in RPG programs. Adopting the map as a standard means that all programs using the external map are coded to respond to the same field names. This makes it easy to interpret the code when it is time to maintain a program.
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* FILE NAME - SCPSTSPF *
* *
* FUNCTION - THIS FILE WAS DESIGNED TO SERVE AS AN EXTERNAL *
* DATA STRUCTURE TO DEFINE THE PROGRAM STATUS *
* DATA STRUCTURE. *
* *
* PROGRAMMER - STEVE CROY 99/99/99 *
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* MODIFICATION LOG *
* *
* DATE PROGRAMMER DESCRIPTION *
* *
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A R RSCPSTS TEXT('PROGRAM STATUS DS')
A PRGNAM 10 COLHDG('PROGRAM' 'NAME')
A STATUS 5S 0 COLHDG('PROGRAM' 'STATUS')
A PRVSTS 5S 0 COLHDG('PREVIOUS' 'STATUS')
A SRCSMT 8 COLHDG('SOURCE' 'STATEMT')
A ROUTIN 8 COLHDG('RPG' 'ROUTINE')
A PARMS 3S 0 COLHDG('NBR OF' 'PARMS')
A MSGID 7 COLHDG('MSG ID')
A INSBNR 4 COLHDG('INSTRUCTION')
A MSGWRK 30 COLHDG('WORK' 'AREA')
A PGMLIB 10 COLHDG('PROGRAM' 'LIBRARY')
A MSGTXT 80 COLHDG('MSG' 'TEXT')
A EXCNBR 4 COLHDG('EXCEPTION' 'NBR')
A FILERR 10 COLHDG('FILE IN' 'ERROR')
A UNUSED1 6 COLDHG('UNUSED')
A ENTDAT 8 COLHDG('DATE' ENTERED')
A DATCEN 2S 0 COLDHDG('CENTURY')
A ERRFIL 8 COLHDG('ERROR' 'FILE')
A ERRINF 35 COLHDG('ERROR' 'DATA')
A JOBNAM 10 COLHDG('JOB' 'NAME')
A USER 10 COLHDG('USER' 'NAME')
A JOBNBR 6 COLHDG('JOB' 'NUMBER')
A JOBDAT 6S 0 COLHDG('JOB' 'DATE')
A SYSDAT 6S 0 COLHDG('SYS' 'DATE')
A SYSTIM 6S 0 COLHDG('SYS' 'TIME')
A PGMDAT 6S 0 COLHDG('PGM' 'TIME')
A PGMTIM 6S 0 COLHDG('PGM' 'TIME')
A CMPLVL 4 COLHDG('COMPILER' 'LVL')
A SRCFIL 10 COLHDG('SOURCE' 'FILE')
A SRCLIB 10 COLHDG('SOURCE' 'LIB')
A SRCMBR 10 COLHDG('SOURCE' 'MEMBER')
A PGMPRC 10 COLHDG('PGM' 'PROC')
A PGMMOD 10 COLHDG('PGM' 'MOD')
A SRCSTBN 2B COLHDG('BIN' 'SRCSTMT')
A SRCIDBN 2B COLHDG('BIN' 'SRCID')
A CURPRF 10 COLHDG('CURR' 'USRPRF')
A EXTERR 4B COLHDG('EXT' 'ERR')
A XMLELM 8B COLHDG('XML' 'ELEMENTS')
A INTJOB 16 COLHDG('INTERNAL' 'JOB ID')
A SYSID 8 COLHDG('SYSTEM' 'NAME')
A UNDEF1 50 COLHDG('UNUSED')
Using the Mapped DS
The code snippetts below illustrate using the mapped PSDS. N* indicated the data structure is not named. But the fields are available to the program. In the subprocedure GETMESSAGE. The program uses the MONITOR block to trap excetions. If an error occurs, the messsge, the message file, and the message text from the PSDS is sent to the program message queue for display.
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* Modification log *
* *
* Date Programmer Description *
* *
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//------------ File section -----------------------------------------
Dcl-F SC0320DF WORKSTN UsrOpn
SFILE(SC0320S1:RRNSI)
INFDS(DSPDS) ;
//------------ Data Structures --------------------------------------
/copy qrpglesrc,SCMAPS_pr
Dcl-DS *N ExtName('SCPSTSPF') PSDS End-DS ;
Dcl-DS DSPDS ExtName('SCDSPFPF') End-DS ;
Dcl-DS functionkey extname('SCKEYSPF') qualified end-DS;
Dcl-DS OBJECT extname('SCOBJSPF') end-DS;
Dcl-DS before extname('SCOBJSPF') qualified end-DS;
Dcl-DS after extname('SCOBJSPF') qualified end-DS;
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//*=====================================================================
Dcl-Proc getMessage ;
Dcl-PI getMessage ;
thisMsg char(7) const ;
end-PI ;
msgID = thisMsg ;
msgdta = *BLANKS;
msg = *BLANKS;
msgf = dftMsgFile;
MONITOR;
RtvMessage(msgid:msgf:msgdta:msg);
msgtxt = msg;
ON-ERROR;
msgf = errFil;
ENDMON;
msgRlq = '*SAME' ;
msgdta = msgtxt;
msgpgm = PRGNAM;
SndMessage(msgid : msgF: msgdta : msgrlq : msgpgm);
MessageToDisplay = *ON;
Return ;
END-Proc getMessage ;
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The PSDS can be a valuable debugging tool. Having the data structued defined can show the compiler information which tells a software engineer when the program was created and from the specific source member of the object in debug mode.