[SQL] C/C++ interface

[Volker Paul]

Hello,

in the C interface documentation there is an example using:

    res = PQexec(conn, "DECLARE mycursor CURSOR FOR select * from
pg_database");
    if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
    {
        fprintf(stderr, "DECLARE CURSOR command failed\n");
        PQclear(res);
        exit_nicely(conn);
    }
    PQclear(res);
    res = PQexec(conn, "FETCH ALL in mycursor");

...etc. So the statements are:

DECLARE mycursor CURSOR FOR select * from pg_database;
FETCH ALL in mycursor;

What's the difference between this and simply doing:
select * from pg_database;

I tried this in psql, the result seemed the same.

What I'm really using, however, is the C++ interface.
Its documentation is not yet complete.
There, too, I tried a version with and without cursor.
The result seems to be the same, but returned int is always 0
for the version without cursor, so I get no information whether
the query succeeded. 

Is someone maintaining the C++ interface and its documentation?


Thanks,

Volker Paul