=over
=item $^M
X
By default, running out of memory is an untrappable, fatal error.
However, if suitably built, Perl can use the contents of C
as an emergency memory pool after Cing. Suppose that your Perl
were compiled with C and used Perl's malloc.
Then
$^M = 'a' x (1 file in the Perl distribution for information on how to
add custom C compilation flags when compiling perl. To discourage casual
use of this advanced feature, there is no L long name for
this variable.
This variable was added in Perl 5.004.
=back