Creates a temporary file with a unique name in read-write (w+) mode and returns a file handle.
The file is automatically removed when closed (for example, by calling fclose, or when there are no remaining references to the file handle returned by tmpfile), or when the script ends.
If the script terminates unexpectedly, the temporary file may not be deleted.
This function has no parameters.
Returns a file handle, similar to the one returned by fopen, for the new file or false on failure.