eio_seek

(PECL eio >= 0.5.0b)

eio_seek — Repositions the offset of the open file associated with the fd argument to the argument offset according to the directive whence

說明

eio_seek(
    mixed $fd,
    int $offset,
    int $whence,
    int $pri = EIO_PRI_DEFAULT,
    callable $callback = NULL,
    mixed $data = NULL
): resource

eio_seek() repositions the offset of the open file associated with stream, Socket resource, or file descriptor specified by fd to the argument offset according to the directive whence as follows:

  • EIO_SEEK_SET - Set position equal to offset bytes.
  • EIO_SEEK_CUR - Set position to current location plus offset.
  • EIO_SEEK_END - Set position to end-of-file plus offset.

參數(shù)

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(yōu)先級：EIO_PRI_DEFAULT，EIO_PRI_MIN，EIO_PRI_MAX 或 null。如果是 null，pri 將設(shè)為 EIO_PRI_DEFAULT。

callback

callback 函數(shù)在請求完成時被調(diào)用。其應(yīng)匹配一下原型：

void callback(mixed $data, int $result[, resource $req]);
data

傳遞給請求的用戶數(shù)據(jù)。

result

針對請求的結(jié)果的值。通常是相應(yīng)的系統(tǒng)調(diào)用返回的值。

req

可選的請求資源，可被 eio_get_last_error() 之類的函數(shù)使用。

data

Arbitrary variable passed to callback.

返回值

eio_seek() returns request resource on success, 或者在失敗時返回 false.