Identical to calling fopen(), fwrite(), and fclose() successively.
You can also specify the data parameter as an array (not multi-dimension arrays). This is equivalent to file_put_contents($filename, implode('', $array)).
As of PHP 5.1.0, you may also pass a stream resource to the data parameter. In result, the remaining buffer of that stream will be copied to the specified file. This is similar with using stream_copy_to_stream().
The file name where to write the data
The data to write. Can be either a string, an array or a stream resource (explained above).
flags can take FILE_USE_INCLUDE_PATH, FILE_APPEND and/or LOCK_EX (acquire an exclusive lock), however the FILE_USE_INCLUDE_PATH option should be used with caution.
A context resource
The function returns the amount of bytes that were written to the file, or FALSE on failure.
Note: This function is binary-safe.
Note: Context support was added with PHP 5.0.0. For a description of contexts, refer to Reference CLIII, Stream Functions.
Tip: You can use a URL as a filename with this function if the fopen wrappers have been enabled. See fopen() for more details on how to specify the filename and Appendix M for a list of supported URL protocols.