(PECL sync >= 1.1.0)
SyncSharedMemory::read — Copy data from named shared memory
$start = 0
[, integer $length
]] )Copies data from named shared memory.
startThe start/offset, in bytes, to begin reading.
Note:
If the value is negative, the starting position will begin at the specified number of bytes from the end of the shared memory segment.
lengthThe number of bytes to read.
Note:
If unspecified, reading will stop at the end of the shared memory segment.
If the value is negative, reading will stop the specified number of bytes from the end of the shared memory segment.
A string containing the data read from shared memory.
Example #1 SyncSharedMemory::__construct() example
<?php
// You will probably need to protect shared memory with other synchronization objects.
// Shared memory goes away when the last reference to it disappears.
$mem = new SyncSharedMemory("AppReportName", 1024);
if ($mem->first())
{
// Do first time initialization work here.
}
$result = $mem->write("report.txt");
$result = $mem->read(3, -4);
var_dump($result);
?>
以上例程的输出类似于：
string(3) "ort"