(PHP 5 >= 5.1.0, PHP 7, PHP 8)
SplFileObject::fwrite — Write to file
$data, int $length = 0): int|false
   Writes the contents of string to the file
  
dataThe string to be written to the file.
length
       If the length argument is given, writing will
       stop after length bytes have been written or
       the end of string is reached, whichever comes
       first.
      
   Returns the number of bytes written, or false on error.
  
| 版本 | 说明 | 
|---|---|
| 7.4.0 | The function now returns falseinstead of zero on failure. | 
示例 #1 SplFileObject::fwrite() example
<?php
$file = new SplFileObject("fwrite.txt", "w");
$written = $file->fwrite("12345");
echo "Wrote $written bytes to file";
?>
以上例程的输出类似于:
Wrote 5 bytes to file