$^M

By default, running out of memory is an untrappable, fatal error. 

However, if suitably built, Perl can use the contents of $^M as an eme
+rgency memory pool after die()ing.

 Suppose that your Perl were compiled with -DPERL_EMERGENCY_SBRK and u
+sed Perl's malloc. 

Then

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

would allocate a 64K buffer for use in an emergency.
See the INSTALL file in the Perl distribution for information on how t
+o add custom C compilation flags when compiling perl.

To discourage casual use of this advanced feature, there is no English
+ long name for this variable.
[download]

In my experience with similar things, the idea is that your code gets called (via signal or callback) when the program dips into the emergency pool ($^M). It should then immediately rummage around and try to free stuff, then try to reallocate the emergency pool. If it fails, then you're probably doomed.

Unfortunately, I don't see a relevant callback for $^M. If so, then there's no way to tell when $^M has been used, and I don't see how it can be useful.

If so, then there's no way to tell when $^M has been used, and I don't see how it can be useful.

I reached a similar conclusion a while ago: Is $^M a leftover April Fool? :(

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

perldiag says:

Out of memory!

(X) The malloc() function returned 0, indicating there was insufficien
+t remaining memory (or virtual memory) to satisfy the request. Perl h
+as no option but to exit immediately.

At least in Unix you may be able to get past this by increasing your p
+rocess datasize limits: in csh/tcsh use limit and limit datasize n (w
+here n is the number of kilobytes) to check the current limits and ch
+ange them, and in ksh/bash/zsh use ulimit -a and ulimit -d n , respec
+tively.
[download]

But maybe you can fork the process out and capture the output/exit code.

-- Frank

One idea would be to write a Perl script which is calling a other Perl script using system( ) inside eval and test if it's returns an error. However this wouldn't be very clean and portable. Untested.