Re: The problems of PQhost()

On Wed, Jan 22, 2014 at 11:48:26PM +0900, Fujii Masao wrote:
> (3) PQhost() cannot return the hostaddr.

> We can fix the problem (3) by changing PQhost() so that it also
> returns the hostaddr. But this change might break the existing
> application using PQhost(). So, I added new libpq function PQhostaddr()
> which returns the hostaddr, and changed \conninfo so that it reports
> correct connection information by using both PQhost() and PQhostaddr().

> + <varlistentry id="libpq-pqhostaddr">
> + <term>
> + <function>PQhostaddr</function>
> + <indexterm>
> + <primary>PQhostaddr</primary>
> + </indexterm>
> + </term>
> +
> + <listitem>
> + <para>
> + Returns the server numeric IP address or host name of the connection.
> + <synopsis>
> + char *PQhostaddr(const PGconn *conn);
> + </synopsis>
> + </para>
> + </listitem>
> + </varlistentry>

From reading this documentation, I assumed this function would return a
non-empty value for every TCP connection. After all, every TCP connection has
a peer IP address. In fact, PQhostaddr() returns the raw value of the
"hostaddr" connection parameter, whether from a libpq function argument or
from the PGHOSTADDR environment variable. (If the parameter and environment
variable are absent, it returns NULL. Adding "hostaddr=" to the connection
string makes it return the empty string.) A caller wanting the specific raw
value of a parameter could already use PQconninfo(). I suspect this new
function will confuse more than help. What do you think of reverting it and
having \conninfo use PQconninfo() to discover any "hostaddr" value?