MDAC 2.5 SDK - ODBC Programmer's Reference
Appendix G: Driver Guidelines for Backward Compatibility
When an application calls SQLAllocStmt through an ODBC 3.x driver, the call to:
SQLAllocStmt(hdbc, phstmt)
is mapped to SQLAllocHandle by the Driver Manager in the driver as follows:
SQLAllocHandle(SQL_HANDLE_STMT, InputHandle, OutputHandlePtr)
with InputHandle set to hdbc and OutputHandlePtr set to phstmt.