using libpq to explain a prepared statement

[lish...@gmail.com]

Hi,

I am trying to send the following query to postgresql through libpq:

EXPLAIN (FORMAT json, COSTS false) EXECUTE \"" + prepared_statement_name + "\" ($1, $2)"

I tried to plug in the query to PQsendQueryParams, it reports the error "bind message supplies 2 parameters, but prepared statement “” requires 0"

Other than sending it as raw query.
Does anyone know how I could make PQsendQueryParams work with explain prepared_statement ?

Thanks,
Lishi

p.s. Using PQsendQueryPrepared to run the plain "prepared_statement_name" is working properly.