(PECL sync >= 1.1.0)
SyncSharedMemory::first — Check to see if the object is the first instance system-wide of named shared memory
Retrieves the system-wide first instance status of a SyncSharedMemory object.
此函数没有参数。
成功时返回 true， 或者在失败时返回 false。
Example #1 SyncSharedMemory::first() example
<?php
$mem = new SyncSharedMemory("AppReportName", 1024);
if ($mem->first())
{
// Do first time initialization work here.
}
var_dump($mem->first());
$mem2 = new SyncSharedMemory("AppReportName", 1024);
var_dump($mem2->first());
?>
以上例程的输出类似于：
bool(true) bool(false)