$^M What is it?

iic has asked for the wisdom of the Perl Monks concerning the following question:

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Re: $^M What is it? by repson (Chaplain) on Dec 20, 2000 at 11:56 UTC
According to perlman:perlvar you generally don't. ------------- $^M By default, running out of memory it is not trappable. However, if compiled for this, Perl may use the contents of $^M as an emergency pool after die()ing with this message. Suppose that your Perl were compiled with -DPERL_EMERGENCY_SBRK and used Perl's malloc. Then `$^M = 'a' x (1<<16);` would allocate a 64K buffer for use when in emergency. See the INSTALL file for information on how to enable this option. As a disincentive to casual use of this advanced feature, there is no the English manpage long name for this variable. ---------------- So it is something used just for emergencies and should have no need to appear in general code except possibly mission-critical apps on a machine which is short on memory (so you have enough to continue no matter what other apps are eating memory). Though that scenario should be avoided.	[reply] [d/l]

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Re: $^M What is it?
by repson (Chaplain) on Dec 20, 2000 at 11:56 UTC

$^M = 'a' x (1<<16);

would allocate a 64K buffer for use when in emergency. See the INSTALL file for information on how to enable this option. As a disincentive to casual use of this advanced feature, there is no the English manpage long name for this variable.
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So it is something used just for emergencies and should have no need to appear in general code except possibly mission-critical apps on a machine which is short on memory (so you have enough to continue no matter what other apps are eating memory). Though that scenario should be avoided.

[reply]
[d/l]