(PECL geoip:1.0.1)
geoip_db_avail — Determine if GeoIP Database is available
The geoip_db_avail() function returns if the corresponding GeoIP Database is available and can be opened on disk.
It does not indicate if the file is a proper database, only if it is readable.
The database type as an integer. You can use the various constants defined with this extension (ie: GEOIP_*_EDITION).
Returns TRUE is database exists, FALSE if not found, or NULL on error.
Example#1 A geoip_db_avail() example
This will output the current database version string.
<?php
if (geoip_db_avail(GEOIP_COUNTRY_EDITION))
print geoip_database_info(GEOIP_COUNTRY_EDITION);
?>
上例将输出：
GEO-106FREE 20080801 Build 1 Copyright (c) 2006 MaxMind LLC All Rights Reserved