$^W
variable (documented in the perlvar manpage) controls runtime warnings for a block:
{ local $^W = 0; # temporarily turn off warnings $a = $b + $c; # I know these might be undef }
Note that like all the punctuation variables, you cannot currently use
my
on $^W
, only local.
A new use warnings
pragma is in the works to provide finer control over all this. The curious
should check the perl5-porters mailing list archives for details.