(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.
priThe 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
Die callback-Funktion wird aufgerufen, wenn die Anfrage abgeschlossen ist.
Sie muss dem folgenden Prototyp entsprechen:
void callback(mixed $data, int $result[, resource $req]);datasind die benutzerdefinierten Daten, die an die Anfrage übergeben werden.
resultder anfragespezifische Ergebniswert; im Grunde der Wert, der vom entsprechenden Systemaufruf zurückgegeben wird.
reqist eine optionale Anfrage-Ressource, die in Funktionen wie eio_get_last_error() verwendet werden kann.
data
Arbitrary variable passed to callback.
eio_read() stores read bytes in
result argument of callback
function.
Beispiel #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();
?>Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:
string(5) "34567"