Message-ID: <3A892433.879F40A0@dohle.com>
Date: Tue, 13 Feb 2001 13:10:27 +0100
From: Volker Paul <vpaul@dohle.com>
Organization: Dohle Handelsgruppe Systemberatung GmbH
MIME-Version: 1.0
To: pgsql-sql@postgresql.org
Subject: C/C++ interface
Content-Type: text/plain; charset=us-ascii
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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