EXEC SQL END DECLARE SECTION;

    EXEC SQL CONNECT TO testdb AS con1 USER testuser;
    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL COMMIT;

    EXEC SQL PREPARE stmt1 FROM :query;
    EXEC SQL DECLARE cur1 CURSOR FOR stmt1;
</programlisting>
    </para>

    <para>
     Next, put some values in the input SQLDA for the input
     parameters.  Allocate memory for the input SQLDA, and set the
     number of input parameters to <literal>sqln</literal>.  Store
     type, value, and value length into <literal>sqltype</literal>,
     <literal>sqldata</literal>, and <literal>sqllen</literal> in the
     <literal>sqlvar</literal> structure.

<programlisting>
    /* Create SQLDA structure for input parameters. */
    sqlda2 = (sqlda_t *) malloc(sizeof(sqlda_t) + sizeof(sqlvar_t));
    memset(sqlda2, 0, sizeof(sqlda_t) + sizeof(sqlvar_t));
    sqlda2->sqln = 2; /* number of input variables */

    sqlda2->sqlvar[0].sqltype = ECPGt_char;
    sqlda2->sqlvar[0].sqldata = "postgres";
    sqlda2->sqlvar[0].sqllen  = 8;

    intval = 1;
    sqlda2->sqlvar[1].sqltype = ECPGt_int;
    sqlda2->sqlvar[1].sqldata = (char *)&amp;intval;
    sqlda2->sqlvar[1].sqllen  = sizeof(intval);
</programlisting>
    </para>

    <para>
     After setting up the input SQLDA, open a cursor with the input
     SQLDA.

<programlisting>
    /* Open a cursor with input parameters. */
    EXEC SQL OPEN cur1 USING DESCRIPTOR sqlda2;
</programlisting>
    </para>

    <para>
     Fetch rows into the output SQLDA from the opened cursor.
     (Generally, you have to call <command>FETCH</command> repeatedly
     in the loop, to fetch all rows in the result set.)
<programlisting>
    while (1)
    {
        sqlda_t *cur_sqlda;

        /* Assign descriptor to the cursor  */
        EXEC SQL FETCH NEXT FROM cur1 INTO DESCRIPTOR sqlda1;
</programlisting>
    </para>

    <para>
     Next, retrieve the fetched records from the SQLDA, by following
     the linked list of the <type>sqlda_t</type> structure.
<programlisting>
    for (cur_sqlda = sqlda1 ;
         cur_sqlda != NULL ;
         cur_sqlda = cur_sqlda->desc_next)
    {
        ...
</programlisting>
    </para>

    <para>
     Read each columns in the first record.  The number of columns is
     stored in <structfield>sqld</structfield>, the actual data of the first
     column is stored in <literal>sqlvar[0]</literal>, both members of
     the <type>sqlda_t</type> structure.

<programlisting>
        /* Print every column in a row. */
        for (i = 0; i &lt; sqlda1-&gt;sqld; i++)
        {
            sqlvar_t v = sqlda1->sqlvar[i];
            char *sqldata = v.sqldata;
            short sqllen  = v.sqllen;

            strncpy(name_buf, v.sqlname.data, v.sqlname.length);
            name_buf[v.sqlname.length] = '\0';
</programlisting>
    </para>

    <para>
     Now, the column data is stored in the variable <varname>v</varname>.
     Copy every datum into host variables, looking
     at <literal>v.sqltype</literal> for the type of the column.
<programlisting>
            switch (v.sqltype) {
                int intval;
                double doubleval;
                unsigned long long int longlongval;

                case ECPGt_char:
                    memset(&amp;var_buf, 0, sizeof(var_buf));
                    memcpy(&amp;var_buf, sqldata, (sizeof(var_buf) &lt;= sqllen ? sizeof(var_buf)-1 : sqllen));
                    break;

                case ECPGt_int: /* integer */
                    memcpy(&amp;intval, sqldata, sqllen);
                    snprintf(var_buf, sizeof(var_buf), "%d", intval);
                    break;

                ...

                default:
                    ...
            }

            printf("%s = %s (type: %d)\n", name_buf, var_buf, v.sqltype);
        }
</programlisting>
    </para>

    <para>
     Close the cursor after processing all of records, and disconnect
     from the database.
<programlisting>
    EXEC SQL CLOSE cur1;