(PECL eio >= 0.0.1dev)
eio_read — Read from a file descriptor at given offset
$fd,$length,$offset,$pri,$callback,$data = NULL
eio_read() reads up to length
bytes from fd file descriptor at
offset. The read bytes are stored in
result argument of callback.
fdStream, Socket resource, or numeric file descriptor
lengthMaximum number of bytes to read.
offsetOffset within the file.
pri請求的優(yōu)先級：EIO_PRI_DEFAULT，EIO_PRI_MIN，EIO_PRI_MAX 或 null。如果是
null，pri 將設為
EIO_PRI_DEFAULT。
callback
callback
函數在請求完成時(shí)被調用。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(hù)數據。
result針對請求的結果的值。通常是相應的系統調用返回的值。
req可選的請求資源，可被 eio_get_last_error() 之類(lèi)的函數使用。
data
Arbitrary variable passed to callback.
eio_read() stores read bytes in
result argument of callback
function.
示例 #1 eio_read() example
<?php
// Open a temporary file and write some bytes there
$temp_filename = "eio-temp-file.tmp";
$fp = fopen($temp_filename, "w");
fwrite($fp, "1234567890");
fclose($fp);
/* Is called when eio_read() is done */
function my_read_cb($data, $result) {
global $temp_filename;
// Output read bytes
var_dump($result);
// Close file
eio_close($data);
eio_event_loop();
// Remove temporary file
@unlink($temp_filename);
}
/* Is called when eio_open() is done */
function my_file_opened_callback($data, $result) {
// $result should contain the file descriptor
if ($result > 0) {
// Read 5 bytes starting from third
eio_read($result, 5, 2, EIO_PRI_DEFAULT, "my_read_cb", $result);
eio_event_loop();
} else {
// eio_open() failed
unlink($data);
}
}
// Open the file for reading and writing
eio_open($temp_filename, EIO_O_RDWR, NULL,
EIO_PRI_DEFAULT, "my_file_opened_callback", $temp_filename);
eio_event_loop();
?>
以上例程的輸出類(lèi)似于：
string(5) "34567"