Sync a file segment with disk

说明

resource eio_sync_file_range ( mixed $fd , int $offset , int $nbytes , int $flags [, int $pri = EIO_PRI_DEFAULT [, callable $callback = NULL [, mixed $data = NULL ]]] )

eio_sync_file_range() permits fine control when synchronizing the open file referred to by the file descriptor fd with disk.

参数

fd

File descriptor

offset

The starting byte of the file range to be synchronized

nbytes

Specifies the length of the range to be synchronized, in bytes. If nbytes is zero, then all bytes from offset through to the end of file are synchronized.

flags

A bit-mask. Can include any of the following values: EIO_SYNC_FILE_RANGE_WAIT_BEFORE, EIO_SYNC_FILE_RANGE_WRITE, EIO_SYNC_FILE_RANGE_WAIT_AFTER. These flags have the same meaning as their SYNC_FILE_RANGE_* counterparts(see SYNC_FILE_RANGE(2) man page).

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_sync_file_range() returns request resource on success or FALSE on error.