 Return the version of <SPAN
CLASS="PRODUCTNAME"
>libpq</SPAN
> that is being used.
</P><PRE
CLASS="SYNOPSIS"
>int PQlibVersion(void);</PRE
><P>
     </P
><P
>      The result of this function can be used to determine, at
      run time, if specific functionality is available in the currently
      loaded version of libpq. The function can be used, for example,
      to determine which connection options are available for
      <CODE
CLASS="FUNCTION"
>PQconnectdb</CODE
> or if the <TT
CLASS="LITERAL"
>hex</