# stream_set_write_buffer

(PHP 4 >= 4.3.0, PHP 5, PHP 7)

stream_set_write_buffer — Sets write file buffering on the given stream

### 说明

stream_set_write_buffer ( resource `$stream` , int `$buffer` ) : int

Sets the buffering for write operations on the given `stream` to `buffer` bytes.

### 参数

`stream`

  The file pointer.

`buffer`

  The number of bytes to buffer. If `buffer` is 0 then write operations are unbuffered. This ensures that all writes with fwrite() are completed before other processes are allowed to write to that output stream.

### 返回值

Returns 0 on success, or another value if the request cannot be honored.

### 范例

Example #1 stream_set_write_buffer() example

The following example demonstrates how to use stream_set_write_buffer() to create an unbuffered stream.

    <?php
    $fp = fopen($file, "w");
    if ($fp) {
      if (stream_set_write_buffer($fp, 0) !== 0) {
          // changing the buffering failed
      }
      fwrite($fp, $output);
      fclose($fp);
    }
    ?>

### 参见

- fopen() - 打开文件或者 URL
- fwrite() - 写入文件（可安全用于二进制文件）