ALLOCATE ROW statement
Use the ALLOCATE ROW statement to allocate memory for a row variable. This statement is an extension to the ANSI/ISO standard for SQL. Use this statement with ESQL/C.
Syntax
ALLOCATE ROWvariable
| Element | Description | Restrictions | Syntax |
|---|---|---|---|
| variable | Name of a typed or untyped row variable to allocate | Must be an unallocated Informix® ESQL/C row-type host variable | Language specific |
Usage
The ALLOCATE ROW statement
allocates memory for a host variable that stores row-type data. To
create a row variable, an ESQL/C program must do the following:
- Declare the row variable. The row variable can be a typed or untyped row variable.
- Allocate memory for the row variable with the ALLOCATE ROW statement.
The following example shows how to allocate resources
with the ALLOCATE ROW statement for the typed row variable,
a_row:EXEC SQL BEGIN DECLARE SECTION;
row (a int, b int) a_row;
EXEC SQL END DECLARE SECTION;
. . .
EXEC SQL allocate row :a_row;The ALLOCATE ROW statement sets SQLCODE (the contents of sqlca.sqlcode) to zero (0) if the memory allocation operation was successful, or to a negative error code if the allocation failed.
You must explicitly release
memory with the DEALLOCATE ROW statement. Once you free the row variable
with the DEALLOCATE ROW statement, you can reuse the row variable.
Tip: The ALLOCATE ROW statement allocates
memory for the Informix®
ESQL/C row variable
only. To allocate memory for the Informix®
ESQL/C collection variable,
use the ALLOCATE COLLECTION statement.
When you use the same row variable in multiple function calls without deallocating it, a memory leak on the client computer results. Because there is no way to determine if a pointer is valid when it is passed, Informix® ESQL/C assumes that the pointer is not valid and assigns it to a new memory location.