pg_connection_status()

(PHP 4 >= 4.2.0, PHP 5, PHP 7)

获得连接状态

说明

pg_connection_status(resource $connection): int

pg_connection_status()返回一个连接的状态。可能的状态为PGSQL_CONNECTION_OK和PGSQL_CONNECTION_BAD。

Example #1 pg_connection_status()例子

<?php
    $dbconn = pg_connect("dbname=publisher") or die("Could not connect");
    $stat = pg_connection_status($dbconn);
    echo 'connection_status: '.$stat;
?>

Example #2 pg_connection_status()例子

<?php
    $dbconn = pg_connect("dbname=publisher") or die("Could not connect");
    $stat = pg_connection_status($dbconn);
    echo 'connection_status: '.$stat;
?>

参见pg_connection_busy()。

Being careful with the comparison operators is not enough:
<?php
if (pg_connection_status($link)===PGSQL_CONNECTION_BAD)
  reconnect($link);
?>
 
The reconnect won't be trigged when $link is null.
The manual is just wrong, there are three return values: PGSQL_CONNECTION_OK, PGSQL_CONNECTION_BAD, null

If the connection variable is NULL this function returns 0 in PHP 5.0.2. Havent figured out any more erratic values for the connection variable but be careful.

The wiki page doesn't currently reflect that, but if you're passing PGSQL_CONNECT_ASYNC to pg_connect, creating the connection won't block and transitions through extra states expressed by those constants.
PGSQL_CONNECTION_AUTH_OK
PGSQL_CONNECTION_AWAITING_RESPONSE
PGSQL_CONNECTION_MADE
PGSQL_CONNECTION_SETENV
PGSQL_CONNECTION_SSL_STARTUP
PGSQL_CONNECTION_STARTED

I think zytox is incorrect, at least in PHP 5.0.4.
It returns null, but you have to be careful with your comparison operators.
As an example:
<?php
unset($null);
if (pg_connection_status($null)===PGSQL_CONNECTION_OK)
  echo 'this is not called';
if (pg_connection_status($null)==PGSQL_CONNECTION_OK)
  echo 'this is called because NULL==0 is true';
?>