## 例

`

     bool ob_start ([ callback $output_callback [, int $chunk_size = 0 [, bool $erase = true ]]] )

`

## 説明

This function will turn output buffering on. While output buffering is active no output is sent from the script (other than headers), instead the output is stored in an internal buffer. The contents of this internal buffer may be copied into a string variable using ob_get_contents(). To output what is stored in the internal buffer, use ob_end_flush(). Alternatively, ob_end_clean() will silently discard the buffer contents. Warning Some web servers (e.g. Apache) change the working directory of a script when calling the callback function. You can change it back by e.g. chdir(dirname($_SERVER['SCRIPT_FILENAME'])) in the callback function. Output buffers are stackable, that is, you may call ob_start() while another ob_start() is active. Just make sure that you call ob_end_flush() the appropriate number of times. If multiple output callback functions are active, output is being filtered sequentially through each of them in nesting order.

## 戻り値

Returns TRUE on success or FALSE on failure.