(PECL eio >= 0.0.1dev)
Read from a file descriptor at given offset.
resource eio_read ( mixed $fd, int $length, int $offset, int $pri, callable $callback [, mixed $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.
Parameters:
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:
1 | void callback(mixed $data, int $result[, resource $req]); |
data
Arbitrary variable passed to callback.
Returns:
eio_read() stores read bytes in result argument of callback function.
Examples:
eio_read() example
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | <?php// Open a temporary file and write some bytes there$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 writingeio_open($temp_filename, EIO_O_RDWR, NULL, EIO_PRI_DEFAULT, "my_file_opened_callback", $temp_filename);eio_event_loop();?> |
The above example will output something similar to:
string(5) "34567"
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