Defining Context Variables for Natural RPC

General syntax of DEFINE DATA CONTEXT:

DEFINE DATA
CONTEXT			USING		local-data-area
					parameter-data-area
			context-data-definition
END-DEFINE

This document covers the following topics:

• Function

• Restrictions

• Syntax Description

For an explanation of the symbols used in the syntax diagrams, see Syntax Symbols.

Belongs to Function Group: Natural Remote Procedure Call

Function

The DEFINE DATA CONTEXT statement is used in conjunction with the Natural Remote Procedure Call (RPC). It is used to define variables known as context variables, which are meant to be available to multiple remote subprograms within one conversation, without having to explicitly pass the variables as parameters with the corresponding CALLNAT statements.

A context variable is referenced by its name, and its content is shared by all programming objects executed in one conversation that refer to that name. The variable is allocated by the first executed programming object that contains the definition of the variable and is deallocated when the conversation ends.

Context variables can also be used in a non-conversational CALLNAT. In this case, the context variables only exist during a single invocation of this CALLNAT but the variables can be shared with all its callees.

A context variable is not shared with subprograms that are called within the conversation. If such a subprogram or one of its callees references a context variable, a separate storage area is allocated for this variable.

The optional INIT clause is evaluated in each executed programming object that contains this clause (not only in the programming object that allocates the variable). This is different to the way the INIT works for global variables.

For further information, see Defining a Conversation Context in the Natural Remote Procedure Call documentation.

Restrictions

A context variable must be defined at Level 01. Other levels are only used in a redefinition.

Syntax Description

DEFINE DATA
  CONTEXT USING DATX_L
  CONTEXT USING DATX_P

  ...
END-DEFINE ;

Context Data Definition

Context data can be defined directly within a program or routine. For direct data definition, the following syntax applies:

For further information, see Defining Fields within a DEFINE DATA Statement in the Programming Guide.