abstraction.  Use the accessor
    functions described below to get at the contents of <structname>PGconn</structname>.
    Reference to internal <structname>PGconn</structname> fields using
    <filename>libpq-int.h</filename> is not recommended because they are subject to change
    in the future.
   </para>
  </tip>

  <para>
   The following functions return parameter values established at connection.
   These values are fixed for the life of the connection.  If a multi-host
   connection string is used, the values of <xref linkend="libpq-PQhost"/>,
   <xref linkend="libpq-PQport"/>, and <xref linkend="libpq-PQpass"/> can change if a new connection
   is established using the same <structname>PGconn</structname> object.  Other values
   are fixed for the lifetime of the <structname>PGconn</structname> object.

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

     <listitem>
      <para>
       Returns the database name of the connection.
<synopsis>
char *PQdb(const PGconn *conn);
</synopsis>
      </para>
     </listitem>
    </varlistentry>

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

     <listitem>
      <para>
       Returns the user name of the connection.
<synopsis>
char *PQuser(const PGconn *conn);
</synopsis>
      </para>
     </listitem>
    </varlistentry>

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

     <listitem>
      <para>
       Returns the password of the connection.
<synopsis>
char *PQpass(const PGconn *conn);
</synopsis>
      </para>

      <para>
       <xref linkend="libpq-PQpass"/> will return either the password specified
       in the connection parameters, or if there was none and the password
       was obtained from the <link linkend="libpq-pgpass">password
       file</link>, it will return that.  In the latter case,
       if multiple hosts were specified in the connection parameters, it is
       not possible to rely on the result of <xref linkend="libpq-PQpass"/> until
       the connection is established.  The status of the connection can be
       checked using the function <xref linkend="libpq-PQstatus"/>.
      </para>
     </listitem>
    </varlistentry>

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

     <listitem>
      <para>
       Returns the server host name of the active connection.
       This can be a host name, an IP address, or a directory path if the
       connection is via Unix socket.  (The path case can be distinguished
       because it will always be an absolute path, beginning
       with <literal>/</literal>.)
<synopsis>
char *PQhost(const PGconn *conn);
</synopsis>
      </para>

      <para>
       If the connection parameters specified both <literal>host</literal> and
       <literal>hostaddr</literal>, then <xref linkend="libpq-PQhost"/> will
       return the <literal>host</literal> information.  If only
       <literal>hostaddr</literal> was specified, then that is returned.
       If multiple hosts were specified in the connection parameters,
       <xref linkend="libpq-PQhost"/> returns the host actually connected to.
      </para>

      <para>
       <xref linkend="libpq-PQhost"/> returns <symbol>NULL</symbol> if the
       <parameter>conn</parameter> argument is <symbol>NULL</symbol>.
       Otherwise, if there is an error producing the host information (perhaps
       if the connection has not been fully established or there was an
       error), it returns an empty string.
      </para>

      <para>
       If multiple hosts were specified in the connection parameters, it is
       not possible to rely on the result of <xref linkend="libpq-PQhost"/> until
       the connection is established.  The status