Informix Guide to SQL: Syntax SQL Statements

Use the DEALLOCATE COLLECTION statement to release memory for a collection variable that was previously allocated with the ALLOCATE COLLECTION statement.

Use this statement with ESQL/C.

The DEALLOCATE COLLECTION statement frees all the memory that is associated with the ESQL/C collection variable that variable identifies. You must explicitly release memory resources for a collection variable with DEALLOCATE COLLECTION. Otherwise, deallocation occurs automatically at the end of the program.

The DEALLOCATE COLLECTION statement releases resources for both typed and untyped collection variables.

Tip: The DEALLOCATE COLLECTION statement deallocates memory for an ESQL/C collection variable only. To deallocate memory for an ESQL/C row variable, use the DEALLOCATE ROW statement.

If you deallocate a nonexistent collection variable or a variable that is not an ESQL/C collection variable, an error results. Once you deallocate a collection variable, you can use the ALLOCATE COLLECTION to reallocate resources and you can then reuse a collection variable.

The following example shows how to deallocate resources with the DEALLOCATE COLLECTION statement for the untyped collection variable, a_set:

EXEC SQL BEGIN DECLARE SECTION;
	client collection a_set;
EXEC SQL END DECLARE SECTION;
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EXEC SQL allocate collection :a_set;
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EXEC SQL deallocate collection :a_set;

Related example: refer to the collection variable example in PUT.

Related statements: ALLOCATE COLLECTION and DEALLOCATE ROW

For a discussion of collection data types, see the Informix ESQL/C Programmer's Manual.