In CL procedures and programs, message subfiles are the only type of subfiles supported. Message subfiles let a controlling procedure or program display one or more error messages.
To use subfile message support, run a Send File (SNDF) or Send/Receive File (SNDRCVF) command using the subfile message control record. In the DDS, supply SFLPGMQ data and always have SFLINZ active.
When you use message subfiles in CL procedures and programs, you must name a procedure or program. You cannot specify an * for the SFLPGMQ keyword in DDS. When you specify a procedure or OPM program name, all messages sent to that procedure's or program's message queue are taken from the invocation message queue and placed in the message subfile. All messages associated with the current request are taken from the CALL message queue and placed in the message subfile.