Apparently this function does not return the database name given in the connection string.  I tried this on apache 2.x/php4.3.x/pg7.4.x and apache 1.3.x/php5.x/pg8rc1 and saw this behavior on both setups.(PHP 4, PHP 5, PHP 7, PHP 8)
pg_options — 获得和 connection 相关的选项
   pg_options() 将返回字符串,包含指定 PostgreSQL connection 实例的特定选项。
  
connectionAn PgSql\Connection instance.
When connection is null, the default connection is used.
The default connection is the last connection made by pg_connect()
or pg_pconnect().
As of PHP 8.1.0, using the default connection is deprecated.
   包含 connection 选项的 string。
  
| 版本 | 说明 | 
|---|---|
| 8.1.0 | 现在 connection参数接受 PgSql\Connection
  实例,之前接受 resource。 | 
| 8.0.0 | connection现在可为 null。 | 
示例 #1 pg_options() 示例
<?php
   $pgsql_conn = pg_connect("dbname=mark host=localhost");
   echo pg_options($pgsql_conn);
?>Apparently this function does not return the database name given in the connection string.  I tried this on apache 2.x/php4.3.x/pg7.4.x and apache 1.3.x/php5.x/pg8rc1 and saw this behavior on both setups.