- if (function_exists('sem_get')) {
- self::$semaphore[$fn_name] = sem_get(self::semaphore_key($fn_name));
+ // The second parameter for "sem_acquire" doesn't exist before 5.6.1
+ if (function_exists('sem_get') && version_compare(PHP_VERSION, '5.6.1', '>=')) {
+ self::$semaphore[$fn_name] = sem_get(self::semaphoreKey($fn_name));