Function dpiStmt_fetchRows 

pub unsafe extern "C" fn dpiStmt_fetchRows(
    stmt: *mut dpiStmt,
    maxRows: u32,
    bufferRowIndex: *mut u32,
    numRowsFetched: *mut u32,
    moreRows: *mut c_int,
) -> c_int

Returns the number of rows that are available in the buffers defined for the query. If no rows are currently available in the buffers, an internal fetch takes place in order to populate them, if rows are available. The number of rows fetched into the internal buffers can be set by calling dpiStmt_setFetchArraySize(). If the statement does not refer to a query an error is returned. All columns that have not been defined prior to this call are implicitly defined using the metadata made available when the statement was executed.

This function should be used instead of dpiStmt_fetch() if it is important to control when the internal fetch (and round-trip to the database) takes place.

The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.