The following JCL example writes an SMS data class to the data class definition file. When you next create a data set using the data class named ABC, the attributes will default to the values given here.
//ADDCLASS JOB 'ADD SMS CLASS',CLASS=A,MSGCLASS=A //*------------------------------------------------------------------ //STEP00 EXEC PGM=IKJEFT01 //SYSIN DD DUMMY //SYSTSIN DD * %SMS DATACLAS NAME(ABC) RECFM(FB) LRECL(80) FUNC(ISRT) //SYSPRINT DD SYSOUT=*,HOLD=Y //SYSTSPRT DD SYSOUT=*,HOLD=Y