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(qǐng)求的優(yōu)先級(jí)：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(qǐng)求完成時(shí)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(qǐng)求的用戶數(shù)據(jù)。
result: 針對(duì)請(qǐng)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(qǐng)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(shí)返回 false.