Allocating ODBC handles

The handle types required for ODBC programs are as follows:

Item	Handle type
Environment	SQLHENV
Connection	SQLHDBC
Statement	SQLHSTMT
Descriptor	SQLHDESC

To use an ODBC handle

Call the SQLAllocHandle function.

SQLAllocHandle takes the following parameters:
- an identifier for the type of item being allocated
- the handle of the parent item
- a pointer to the location of the handle to be allocated
  
  For a full description, see SQLAllocHandle in the Microsoft ODBC API Reference at http://msdn.microsoft.com/en-us/library/ms712455.aspx.
Use the handle in subsequent function calls.
Free the object using SQLFreeHandle.

SQLFreeHandle takes the following parameters:
- an identifier for the type of item being freed
- the handle of the item being freed
  
  For a full description, see SQLFreeHandle in the Microsoft ODBC API Reference at http://msdn.microsoft.com/en-us/library/ms710123.aspx.

Example

The following code fragment allocates and frees an environment handle:

SQLHENV env;
SQLRETURN retcode;
retcode = SQLAllocHandle( 
      SQL_HANDLE_ENV, 
      SQL_NULL_HANDLE, 
      &env ); 
if( retcode == SQL_SUCCESS 
    || retcode == SQL_SUCCESS_WITH_INFO ) {
  // success: application Code here
}
SQLFreeHandle( SQL_HANDLE_ENV, env );

For more information about return codes and error handling, see Handling errors.

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