Displaying and monitoring the value of a variable

z/OS® Debugger can display the value of variables in the following ways:

  • One-time display, by using the LIST command, the PF4 key, or the L prefix command. One-time display displays the value of the variable at the moment you enter the LIST command, press the PF4 key, or enter the L prefix command. If you step or run through your program, any changes to the value of the variable are not displayed. The L and M prefix commands are available only when you use the following languages or compilers:
    • Enterprise PL/I for z/OS, Version 3.6 or 3.7 with the PTF for APAR PK70606, or later
    • Enterprise COBOL compiled with the TEST compile option
    • Assembler
    • Disassembly
  • Continuous display, called monitoring, by using the MONITOR LIST command, the SET AUTOMONITOR command, or the M prefix command. If you step or run through your program, any changes to the value of the variable are displayed.
Note: Use the command SET LIST TABULAR to format the LIST output for arrays and structures in tabular format. See the IBM® z/OS Debugger Reference and Messages for more information about this command.

If z/OS Debugger cannot display the value of a variable in its declared data type, see How z/OS Debugger handles characters that cannot be displayed in their declared data type.