eio_readahead
(PECL eio >= 0.0.1dev)
eio_readahead — Perform file readahead into page cache
说明
mixed
$fd,int
$offset,int
$length,int
$pri = EIO_PRI_DEFAULT,callable
$callback = NULL,mixed
$data = NULL): resource
eio_readahead() populates the page cache with data from a file so that subsequent reads from
that file will not block on disk I/O. See READAHEAD(2) man page for details.
参数
fd-
Stream, Socket resource, or numeric file descriptor
offset-
Starting point from which data is to be read.
length-
Number of bytes to be read.
pri-
请求的优先级：
EIO_PRI_DEFAULT，EIO_PRI_MIN，EIO_PRI_MAX或null。如果是null，pri将设为EIO_PRI_DEFAULT。 callback-
callback函数在请求完成时被调用。其应匹配一下原型：void callback(mixed $data, int $result[, resource $req]);data传递给请求的用户数据。
result针对请求的结果的值。通常是相应的系统调用返回的值。
req可选的请求资源，可被 eio_get_last_error() 之类的函数使用。
data-
Arbitrary variable passed to
callback.
返回值
eio_readahead() returns request resource on success, 或者在失败时返回 false.
用户贡献的备注
备份地址：http://www.lvesu.com/blog/php/function.eio-readahead.php