Restrictions when using EDF

When you are using EDF to debug your application programs, you must be aware of a number of restrictions.

Open TCBs and EDF
Even if your program typically runs using an OPEN TCB (L8, L9, X8, or X9), CEDF forces the program to run on the QR TCB, because CEDF itself is not threadsafe.
Parameter list stacking
CEDF only has one level of stacking for its copies of the EXEC CICS parameter list. If an application calls an EXEC-capable global user exit or user-replaceable module (URM), the parameter list for the EXEC CICS commands issued by the global user exit or URM might overlay the parameter list for EXEC CICS commands issued by the main program.
Security considerations

EDF is such a powerful tool that your installation might restrict its use with attach-time security. The external security manager used by your installation defines the security attributes for the EDF transaction. If you are not authorized to use CEDF, you cannot initiate the transaction.

Application prerequisites

User application programs that are to be debugged using EDF must be assembled (or compiled) with the translator option EDF, which is the default. If you specify NOEDF, the program cannot be debugged using EDF. There is no performance advantage in specifying NOEDF, but the option can be useful to prevent commands in already debugged subprograms appearing on EDF displays.

Application programs that are to be debugged using EDF must also have the attribute CEDF(YES) in their resource definition, which is the default. If a program is defined with CEDF(YES) and compiled with the translator option EDF, EDF diagnostic screens are displayed for the program. If the program is defined with CEDF(YES) but compiled with the translator option NOEDF, only the program initiation and termination screens are displayed. If CEDF(NO) is specified, no EDF screens are displayed.

If a program with the attribute CEDF(NO) links to a program with the attribute CEDF(YES), it might not be possible to use EDF for the transaction. For example, if the CICSPlex SM dynamic transaction routing program EYU9XLOP is defined with the attribute CEDF(NO), and the user-replaceable program EYU9WRAM (for workload management processing) is defined with the attribute CEDF(YES), you cannot use EDF to debug EYU9WRAM. For successful debugging of multiple programs within a transaction, ensure that all the programs are defined with CEDF(YES).

Restrictions for single-screen mode

There are some restrictions on the use of EDF that make it preferable or even necessary to use one particular screen mode:
  • EDF can be used only in single-screen mode when running a remote transaction.
  • VM PASSTHRU is not supported by EDF when testing in single-screen mode.
  • In single-screen mode, the user transaction and CEDF must not specify message journaling, because the messages interfere with the EDF displays. Message journaling is controlled by the profile definition for each transaction.
  • In single screen mode, do not specify PROTECT=YES in the profile definition of the CEDF transaction. If this option is specified, message protection for the CEDF transaction is ignored. The user transaction can still specify the PROTECT=YES option even when running under CEDF. This restriction does not apply to dual-screen mode.
  • If a SEND LAST command is issued, EDF is ended before the command is processed if you are using single-screen mode.
  • To test an application program that uses screen partitions, or that does its own request unit (RU) chaining, run in dual-screen mode.
  • In single-screen mode, if the profile for the user transaction specifies INBFMH=ALL or INBFMH=DIP, the profile for CEDF must have the same INBFMH value. Otherwise the user transaction ends with the ADIR abend. Dual-screen mode does not require the profiles to match in this respect.
  • If the inbound reply mode is set to character to enable the attribute setting keys, EDF disables the keys in single-screen mode.
  • When using CECI under EDF in dual-screen mode, certain commands (for example, ASSIGN and ADDRESS) are issued against the EDF terminal and not the transaction terminal. See INVOKE CECI for information about how to invoke CECI from CEDF.
  • When using EDF in dual-screen mode, avoid starting a second task at the EDF terminal, for example by issuing a START command. Because EDF is a pseudoconversational transaction, it does not prevent a second task from starting at the terminal it is using. This might lead to a deadlock in certain circumstances.
  • When using EDF screen suppression in dual screen mode, commands that cause a long wait, such as DELAY, WAIT, or a second RECEIVE, might cause EDF to appear as if it has finished. If the task ends abnormally, EDF is reactivated at the monitoring terminal.

Restrictions for both screen modes

Other restrictions apply to both screen modes:
  • If a transaction issues the FREE command, EDF is switched off without warning.
  • EDF does not intercept calls to the CPI Communications interface (CPI-C) or the SAA Resource Recovery interface (CPI-RR). You can test transactions that use CPI calls under EDF, but you cannot see EDF displays at the call points.
  • When processing a SIGNON command, CEDF suppresses display of the password or password phrase value to reduce the risk of accidental disclosure.
  • When using EDF against a connection, file control commands functions that are shipped over the connection will not be displayed due to the implementation of CEDF.