pan>.temp_file</code></a>, but returns both the name of a fresh
   temporary file, and an output channel opened (atomically) on
   this file.  This function is more secure than <code class="code">temp_file</code>: there
   is no risk that the temporary file will be modified (e.g. replaced
   by a symbolic link) before the program opens it.  The optional argument
   <code class="code">mode</code> is a list of additional flags to control the opening of the file.
   It can contain one or several of <code class