PL/Perlu - list of columns

Hi,

I'am writing pl/perlu function, it executes some query using spi_exec_query.
What I want is to get list of fields even when query does not return any rows.
Now I get this:
 {
          'status' => 'SPI_OK_SELECT',
          'processed' => 0,
          'rows' => []
}
Is there any way to get structure similar to dbi : $stmt->{'TYPE'}?

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Best regards
Sid