Data Manipulation Language Statements › Functions of DML Statements › Data Communications Functions

Data Communications Functions

The following is a list of the 8 data communications DML functions:

• Program management statements:
  • Pass and return control from one program to another
  • Load and delete programs and tables
  • Define exit routines to be performed before an abnormal program termination (abend)
  • Force an abend condition
• Storage management statements allocate and release variable storage.
• Task management statements:
  • Initiate a new task
  • Change the dispatching priority of the issuing task
  • Enqueue and dequeue system resources
  • Signal that a task is to wait pending completion of an event
  • Post an event control block (ECB), indicating completion of an event
• Time management statements obtain the time and date and define time-related events. These events include:
  • Placing the issuing task in a wait state for a specified amount of time
  • Posting a user-specified ECB after a specified interval
  • Initiating a new task after a specified interval
• Scratch management statements create, delete, or retrieve records from the scratch area.
• Queue management statements create, delete, or retrieve records from the queue area.
• Terminal management statements transfer data between the application program and the terminal.
• Utility function statements:
  • Request retrieval of task-related information
  • Request a memory dump of selected parts of storage
  • Retrieve and send a predefined message stored in the data dictionary
  • Send a specified message to one or more users or logical terminals
  • Collect, retrieve, and write DC/UCF system statistics on a transaction basis
  • Establish longterm database locks and monitor access to database records used across tasks during a pseudo-conversational transaction