Re: Examples of using PQexecParams - Mailing list pgsql-general

From John R Pierce
Subject Re: Examples of using PQexecParams
Date
Msg-id 4B1967EB.1010300@hogranch.com
Whole thread Raw
In response to Examples of using PQexecParams  (Daniel <danwgrace@gmail.com>)
List pgsql-general
Daniel wrote:
> I was looking for examples of using PQexecParams but all I found was
> this: http://sepp.oetiker.ch/postgresql-8.2.3-ds/libpq-example.html
>
> /* Convert integer value "2" to network byte order */
>     binaryIntVal = htonl((uint32_t) 2);
> /* Set up parameter arrays for PQexecParams */
>     paramValues[0] = (char *) &binaryIntVal;
>     paramLengths[0] = sizeof(binaryIntVal);
>     paramFormats[0] = 1;        /* binary */
> ...
> seems a bit convoluted.
>
> In particular I was looking for an example of setting up a string
> parameter for PQexecParams, assuming that is possible.
>

strings don't need to be passed in binary, so its a lot simpler.

see example 30-3 on
http://www.postgresql.org/docs/current/static/libpq-example.html

    const char *paramValues[1];

   /* Here is our out-of-line parameter value */
    paramValues[0] = "joe's place";

    res = PQexecParams(conn,
                       "SELECT * FROM test1 WHERE t = $1",
                       1,       /* one param */
                       NULL,    /* let the backend deduce param type */
                       paramValues,
                       NULL,    /* don't need param lengths since text */
                       NULL,    /* default to all text params */
                       0);      /* ask for text results */



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