=over =item $^M By default, running out of memory is an untrappable, fatal error. However, if suitably built, Perl can use the contents of C<$^M> as an emergency memory pool after die()ing. Suppose that your Perl were compiled with -DPERL_EMERGENCY_SBRK and used Perl's malloc. Then $^M = 'a' x (1 << 16); would allocate a 64K buffer for use in an emergency. See the F file in the Perl distribution for information on how to enable this option. To discourage casual use of this advanced feature, there is no L long name for this variable. =back