Using Language Environment MSGFILE

Runtime messages are directed to a common Language Environment message file. You can use the MSGFILE runtime option to specify the ddname of this file. If a message file ddname is not declared, messages are written to the IBM-supplied default ddname SYSOUT.

The definitions of MSGFILE(SYSOUT) differ, depending on the operating system you use. Table 1 lists the SYSOUT definitions and MSGFILE default attributes for MVS™ and TSO/E:

Table 1. Operating system, SYSOUT definitions, MSGFILE default attributes
Operating system	SYSOUT definition	MSGFILE default attributes
MVS	SYSOUT=* The output is routed to the destination specified in the MSGCLASS option of the JOB card.	LRECL 121, RECFM FBA If not a terminal, BLKSIZE 121*100; if a terminal, BLKSIZE 121.
TSO/E	ALLOC DD(SYSOUT) DA(*)	LRECL 121, RECFM FBA, BLKSIZE 121

When you direct runtime messages to an I/O device, the method you should use also depends on the operating system. Table 2 lists methods for directing runtime messages to an I/O device under MVS and TSO/E, and provides references for additional information about this topic.

Table 2. Defining an I/O device for a ddname
Operating system	Method to define I/O device	For more information, see:
MVS	Specify the ddname of a data set in the JCL.	"Required DD Statements" in Writing JCL for the link-edit process
TSO/E	The ddname of the data set that you specify using the ALLOCATE command.	Creating and executing programs under TSO/E

Note:

You need to modify existing JCL of pre-Language Environment-conforming applications in order to define new ddnames for MSGFILE.
You can specify the same message file across nested enclaves. Language Environment coordinates the use of the same ddname across nested enclaves. If you specify different MSGFILE ddnames in each enclave, Language Environment honors each ddname.
The Language Environment® MSGFILE can be allocated to a large format sequential data set.
Under CICS®, the MSGFILE runtime option is ignored. All runtime messages are directed to a transient data queue named CESE rather than to the ddname specified in the MSGFILE option. For more information about message handling and runtime message output under CICS, see Runtime output under CICS.