(mongodb >=1.2.0)
MongoDB\BSON\ObjectId::getTimestamp — Returns the timestamp component of this ObjectId
The timestamp component of an ObjectId is its most significant 32 bits, which denotes the number of seconds since the Unix epoch. This value is read as an unsigned 32-bit integer with big-endian byte order.
Note: Because PHP's integer type is signed, some values returned by this method may appear as negative integers on 32-bit platforms. The "%u" formatter of sprintf() may be used to obtain a string representation of the unsigned decimal value.
此函数没有参数。
Returns the timestamp component of this ObjectId.
Example #1 MongoDB\BSON\ObjectId::getTimestamp() example
<?php
var_dump((new MongoDB\BSON\ObjectId())->getTimestamp());
var_dump((new MongoDB\BSON\ObjectId('0000002a0000000000000000'))->getTimestamp());
?>
以上例程的输出类似于：
integer(1484854719) integer(42)