Dynamic output

Note: You can use dynamic output in a JES2 environment or a JES3 4.2.1 or later environment.
Before a program writes to a system output (SYSOUT) data set, the program must:
  1. Describe the processing options for the SYSOUT data set. This means giving the system information such as what kind of print paper to use, how many copies, how many lines on a page, and so forth.
  2. Allocate the data set.
  3. Open the data set.

The first step in the sequence, describing the SYSOUT processing options for the data set, can be accomplished before the program executes by using an OUTPUT JCL statement. However, by using dynamic output, a program can describe its SYSOUT processing options during program execution.

The second step in the sequence, allocating the data set, can also be accomplished in two ways. Before execution, you can allocate by using the DD JCL statement. During execution, you can allocate by using dynamic allocation.

To accomplish both steps dynamically, use dynamic allocation with dynamic output. When you use them together, the available processing options are similar to the options available through the OUTPUT and DD JCL statements. For example, you can use dynamic output with dynamic allocation to describe the same SYSOUT characteristics that you could describe by using the following JCL: 
//OUT1    OUTPUT COPIES=10,DEST=FRANCE
//DD1     DD     SYSOUT=A,OUTPUT=*.OUT1
Dynamic output has two advantages:
  • Flexibility — Dynamic output lets the application change the SYSOUT processing options based on input data to the application when the application executes. It provides more flexibility than the OUTPUT JCL statement, which requires you to specify the SYSOUT processing options before the application executes.
  • Convenience — Dynamic output allows you to write your application program so that it changes your SYSOUT processing options based on the input your program receives. This eliminates the need to change your JCL OUTPUT statement for each of your SYSOUT processing requirements.

Dynamic output affects only SYSOUT data sets. The programs that invoke dynamic output can be authorized or unauthorized. To use dynamic output, issue the OUTADD and OUTDEL macros.

For information on the OUTPUT JCL statement, see z/OS MVS JCL Reference. For general information on JCL, see z/OS MVS JCL User's Guide.

Note: BPXWDYN is a text interface to a subset of the SVC 99 (dynamic allocation) and SVC 109 (dynamic output) services. BPXWDYN supports data set allocation, unallocation, concatenation, and the addition and deletion of output descriptors. BPXWDYN is designed to be called from REXX, but it may be called from several other programming languages, including Assembler, C, and PL/I. For more information, see z/OS Using REXX and z/OS UNIX System Services.