open(TMP, "+>", undef) or die ...
-opens a filehandle to an anonymous temporary file. Also using "+<"
-works for symmetry, but you really should consider writing something
-to the temporary file first. You will need to seek() to do the
-reading. Starting from Perl 5.8.1 the temporary files are created
-using the File::Temp module for greater portability, in Perl 5.8.0 the
-mkstemp() system call (which has known bugs in some platforms) was used.
+opens a filehandle to an anonymous temporary file.
File handles can be opened to "in memory" files held in Perl scalars via: