Debugging subtasks created by the ATTACH assembler macro

Under certain circumstances, you can debug multi-tasked applications that create their subtasks by using the ATTACH assembler macro. To debug subtasks, the following conditions must be met:
  • SVC screening must be in effect. For information about enabling SVC screening for your task, see SVCSCREEN in Chapter 15. EQAOPTS commands in the IBM® z/OS Debugger Customization Guide.
  • Delay debug mode must be active or INSPPREF DD must be allocated.
  • If the main program of the top-level task is not Language Environment-compliant, you must start the program by using EQANMDBG. For information about using EQANMDBG to start z/OS® Debugger for non-Language Environment-compliant programs, see Starting z/OS Debugger for programs that start outside of Language Environment.
To debug a program in the main task or in a subtask of the main task, you must enter pattern matching arguments in the delay debug profile data set that matches one of the programs that executes in the subtask.

Usage notes:

  • Each task to be debugged in an address space uses an entirely separate copy of z/OS Debugger. Therefore, commands such as LIST CALLS provide information only about the current task. z/OS Debugger does not provide information about any tasks that precede the current task in the parent chain.
  • For remote debug users, each task is displayed in the Debug view as a separate "Incoming debug session".
  • 3270 users can log on to the Terminal Interface Manager on multiple terminals using the same user ID. For each task to be debugged, a z/OS Debugger session starts on an available terminal if the following conditions are met:
    • The user chose full-screen mode using the Terminal Interface Manager in the delay debug profile.
    • The terminal that the user logged on is available, and is not in a z/OS Debugger session.