Reflects if safe locale operations are available to this perl (when the value is 1) or not (the value is 0). This variable is always 1 if the perl has been compiled without threads. It is also 1 if this perl is using thread-safe locale operations. Note that an individual thread may choose to use the global locale (generally unsafe) by calling "switch_to_global_locale" in perlapi. This variable currently is still set to 1 in such threads.
This variable is read-only.
This variable was added in Perl v5.28.0.