<productname>PostgreSQL</productname>
       installation's <filename>include</filename> directory.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="libpq-PQfmod">
     <term><function>PQfmod</function><indexterm><primary>PQfmod</primary></indexterm></term>

     <listitem>
      <para>
       Returns  the type modifier of the column associated with the
       given column number.  Column numbers start at 0.
<synopsis>
int PQfmod(const PGresult *res,
           int column_number);
</synopsis>
      </para>

      <para>
       The interpretation of modifier values is type-specific; they
       typically indicate precision or size limits.  The value -1 is
       used to indicate <quote>no information available</quote>.  Most data
       types do not use modifiers, in which case the value is always
       -1.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="libpq-PQfsize">
     <term><function>PQfsize</function><indexterm><primary>PQfsize</primary></indexterm></term>

     <listitem>
      <para>
       Returns  the  size  in bytes of the column associated with the
       given column number.  Column numbers start at 0.
<synopsis>
int PQfsize(const PGresult *res,
            int column_number);
</synopsis>
      </para>

      <para>
       <xref linkend="libpq-PQfsize"/> returns the space allocated for this column
       in a database row, in other words the size of the server's
       internal representation of the data type.  (Accordingly, it is
       not really very useful to clients.) A negative value indicates
       the data type is variable-length.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="libpq-PQbinaryTuples">
     <term><function>PQbinaryTuples</function><indexterm><primary>PQbinaryTuples</primary></indexterm></term>

     <listitem>
      <para>
       Returns 1 if the <structname>PGresult</structname> contains binary data
       and 0 if it contains text data.
<synopsis>
int PQbinaryTuples(const PGresult *res);
</synopsis>
      </para>

      <para>
       This function is deprecated (except for its use in connection with
       <command>COPY</command>), because it is possible for a single
       <structname>PGresult</structname> to contain text data in some columns and
       binary data in others.  <xref linkend="libpq-PQfformat"/> is preferred.
       <xref linkend="libpq-PQbinaryTuples"/> returns 1 only if all columns of the
       result are binary (format 1).
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="libpq-PQgetvalue">
     <term><function>PQgetvalue</function><indexterm><primary>PQgetvalue</primary></indexterm></term>

     <listitem>
      <para>
       Returns a single field value of one row of a
       <structname>PGresult</structname>.  Row and column numbers start
       at 0.  The caller should not free the result directly.  It will
       be freed when the associated <structname>PGresult</structname> handle is
       passed to <xref linkend="libpq-PQclear"/>.
<synopsis>
char *PQgetvalue(const PGresult *res,
                 int row_number,
                 int column_number);
</synopsis>
      </para>

      <para>
       For data in text format, the value returned by
       <xref linkend="libpq-PQgetvalue"/> is a null-terminated character
       string  representation of the field value.  For data in binary
       format, the value is in the binary representation determined by
       the data type's <function>typsend</function> and <function>typreceive</function>
       functions.  (The value is actually followed by a zero byte in
       this case too, but that is not ordinarily useful, since the
       value is likely to contain embedded nulls.)
      </para>

      <para>
       An empty string is returned if the field value is null.  See
       <xref linkend="libpq-PQgetisnull"/> to distinguish null values from
       empty-string values.
      </para>

      <para>
       The pointer