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<?xml version="1.0" encoding="ISO-8859-1"?>
<!--
-
- This file is part of the OpenLink Software Virtuoso Open-Source (VOS)
- project.
-
- Copyright (C) 1998-2018 OpenLink Software
-
- This project is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the
- Free Software Foundation; only version 2 of the License, dated June 1991.
-
- This program is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-
-
-->
<refentry id="fn_bif_arg">
<refmeta>
<refentrytitle>Virtuoso Server Extension Interface (VSEI) functions</refentrytitle>
<refmiscinfo>bif</refmiscinfo>
</refmeta>
<refnamediv>
<refname>bif_arg</refname>
<refname>bif_array_arg</refname>
<refname>bif_array_or_null_arg</refname>
<refname>bif_bin_arg</refname>
<refname>bif_double_arg</refname>
<refname>bif_entity_arg</refname>
<refname>bif_float_arg</refname>
<refname>bif_long_arg</refname>
<refname>bif_long_or_char_arg</refname>
<refname>bif_string_arg</refname>
<refname>bif_string_or_null_arg</refname>
<refname>bif_string_or_wide_or_null_arg</refname>
<refname>bif_strses_arg</refname>
<refpurpose>Get parameters for built in function</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis id="fsyn_bif_arg">
<funcprototype id="fproto_bif_arg">
<funcdef>caddr_t <function>bif_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_array_arg">
<funcprototype id="fproto_bif_array_arg">
<funcdef>caddr_t <function>bif_array_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_array_or_null_arg">
<funcprototype id="fproto_bif_array_or_null_arg">
<funcdef>caddr_t <function>bif_array_or_null_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_bin_arg">
<funcprototype id="fproto_bif_bin_arg">
<funcdef>caddr_t <function>bif_bin_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_double_arg">
<funcprototype id="fproto_bif_double_arg">
<funcdef>caddr_t <function>bif_double_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_entity_arg">
<funcprototype id="fproto_bif_entity_arg">
<funcdef>caddr_t <function>bif_entity_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_float_arg">
<funcprototype id="fproto_bif_float_arg">
<funcdef>caddr_t <function>bif_float_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_long_arg">
<funcprototype id="fproto_bif_long_arg">
<funcdef>caddr_t <function>bif_long_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_long_or_char_arg">
<funcprototype id="fproto_bif_long_or_char_arg">
<funcdef>caddr_t <function>bif_long_or_char_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_string_arg">
<funcprototype id="fproto_bif_string_arg">
<funcdef>caddr_t <function>bif_string_arg</function></funcdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_string_or_null_arg">
<funcprototype id="fproto_bif_string_or_null_arg">
<funcdef>caddr_t <function>bif_string_or_null_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_string_or_wide_or_null_arg">
<funcprototype id="fproto_bif_string_or_wide_or_null_arg">
<funcdef>caddr_t <function>bif_string_or_wide_or_null_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_bif_strses_arg">
<funcprototype id="fproto_bif_strses_arg">
<funcdef>caddr_t <function>bif_strses_arg</function></funcdef>
<paramdef>caddr_t * <parameter>qst</parameter></paramdef>
<paramdef>state_slot_t ** <parameter>args</parameter></paramdef>
<paramdef>int <parameter>nth</parameter></paramdef>
<paramdef>char * <parameter>func</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="desc_bif_arg"><title>Description</title>
<para>The bif_...._arg functions are used in the Virtuoso shared object. They allow
customization of the Virtuoso server.
They are written in C code, and linked with the Virtuoso shared object.</para>
<para>The _or_null_ variants of these functions represent the SQL null
value as a 00 pointer, even though getting the same argument with bif_arg()
would return a box with the DV_DB_NULL tag.
All number functions will coerce other types of numbers to the result type.
All array argument functions will accept any type of array. It is up to the
VSE itself to distinguish.</para>
<para>Virtuoso Server Extensions (VSEs) were formally referred to as Built-In Functions (BIFs).</para>
</refsect1>
<refsect1 id="params_bif_arg">
<title>Parameters</title>
<refsect2>
<title>qst</title>
<para>Query instance.</para>
</refsect2>
<refsect2>
<title>args</title>
<para>input arguments.</para>
</refsect2>
<refsect2>
<title>nth</title>
<para>which argument to retrieve (zero indexed).</para>
</refsect2>
<refsect2>
<title>func</title>
<para>name of calling function. This will be printed in the SQL error message.</para>
</refsect2>
</refsect1>
<refsect1 id="ret_bif_arg"><title>Return Values</title>
<para>On success, return a valid pointer to the data retrieved, or NULL.
A SQL error is generated if the datatype is not valid.
The bif_arg is the only function not to have validation of a data type.</para>
<para>The values returned by any of these belong to the query instance, and the bif
is not authorized to modify or free them.</para>
<table><title>Return types</title>
<tgroup cols="2">
<thead>
<row><entry>Function</entry><entry>Type validated and returned</entry></row>
</thead>
<tbody>
<row>
<entry>bif_arg</entry>
<entry>Any type of data. (no data type check)</entry>
</row>
<row>
<entry>bif_array_arg</entry>
<entry>string or array data</entry>
</row>
<row>
<entry>bif_array_or_null_arg</entry>
<entry>string or array or NULL data</entry>
</row>
<row>
<entry>bif_bin_arg</entry>
<entry>binary data</entry>
</row>
<row>
<entry>bif_double_arg</entry>
<entry>double data</entry>
</row>
<row>
<entry>bif_entity_arg</entry>
<entry>XML entity data</entry>
</row>
<row>
<entry>bif_float_arg</entry>
<entry>float data</entry>
</row>
<row>
<entry>bif_long_arg</entry>
<entry>long data</entry>
</row>
<row>
<entry>bif_long_or_char_arg</entry>
<entry>long or character data</entry>
</row>
<row>
<entry>bif_string_arg</entry>
<entry>string data</entry>
</row>
<row>
<entry>bif_string_or_null_arg</entry>
<entry>string or null data</entry>
</row>
<row>
<entry>bif_string_or_wide_or_null_arg</entry>
<entry>strings, widestrings or null data</entry>
</row>
<row>
<entry>bif_strses_arg</entry>
<entry>string session data</entry>
</row>
</tbody>
</tgroup>
</table>
</refsect1>
<refsect1 id="examples_bif_arg"><title>Examples</title>
<example id="ex_bif_len">
<title>Creating a function my_length()</title>
<para>A function called <function>my_length</function> written by developers, may process
a string argument by making a call to
<function>bif_string_arg</function>.</para>
</example>
</refsect1>
</refentry>
|
