Bert Horvath <bert(dot)horvath(at)fh-erfurt(dot)de> writes:
> Small example:
> create table foo(bar integer);
> insert into foo values(1),(2),(3);
> res = PQexec(conn, "COPY foo TO stdout;");
> if ( PQresultStatus( res ) == PGRES_COPY_OUT )
> {
> printf("RowCount: ");
> printf("%s\n",PQcmdTuples(res)); // this is NULL
> ...
Wrong result --- at that point you've only started the COPY, not
completed it, so how would it know how many rows there are?
You need to look at the PGRES_COMMAND_OK result after the COPY.
regards, tom lane