eio_read

(PECL eio >= 0.0.1dev)

eio_read — Read from a file descriptor at given offset

Açıklama

eio_read(
    mixed $fd,
    int $length,
    int $offset,
    int $pri,
    callable $callback,
    mixed $data = NULL
): resource

eio_read() reads up to length bytes from fd file descriptor at offset. The read bytes are stored in result argument of callback.

Bağımsız Değişkenler

fd

Stream, Socket resource, or numeric file descriptor

length

Maximum number of bytes to read.

offset

Offset within the file.

pri

The request priority: EIO_PRI_DEFAULT, EIO_PRI_MIN, EIO_PRI_MAX, or null. If null passed, pri internally is set to EIO_PRI_DEFAULT.

callback

callback function is called when the request is done. It should match the following prototype:

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

data: is custom data passed to the request.
result: request-specific result value; basically, the value returned by corresponding system call.
req: is optional request resource which can be used with functions like eio_get_last_error()

data

Arbitrary variable passed to callback.

Dönen Değerler

eio_read() stores read bytes in result argument of callback function.

Örnekler

Örnek 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();
?>

Yukarıdaki örnek şuna benzer bir çıktı üretir:

string(5) "34567"

Ayrıca Bakınız

eio_open() - Opens a file
eio_write() - Write to file
eio_close() - Close file
eio_event_loop() - Polls libeio until all requests proceeded

add a note

User Contributed Notes

There are no user contributed notes for this page.