eio_readahead
(PECL eio >= 0.0.1dev)
eio_readahead — Perform file readahead into page cache
說明
eio_readahead(
mixed
int
int
int
callable
mixed
): resource
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.
參數
-
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 -
請求的優先順序：
EIO_PRI_DEFAULT，EIO_PRI_MIN，EIO_PRI_MAX或null。如果是null，pri將設為EIO_PRI_DEFAULT。 -
callback -
callback函式在請求完成時被呼叫。其應匹配一下原型：void callback(mixed $data, int $result[, resource $req]);-
data -
傳遞給請求的用戶數據。
-
result -
針對請求的結果的值。通常是相應的系統呼叫返回的值。
-
req -
可選的請求資源，可被 eio_get_last_error() 之類的函式使用。
-
-
data -
Arbitrary variable passed to
callback.
返回值
eio_readahead() returns request resource on success, 或者在失敗時返回 false.