=item C<setlocale>
+WARNING! Do NOT use this function in a L<thread|threads>. The locale
+will change in all other threads at the same time, and should your
+thread get paused by the operating system, and another started, that
+thread will not have the locale it is expecting. On some platforms,
+there can be a race leading to segfaults if two threads call this
+function nearly simultaneously.
+
Modifies and queries the program's underlying locale. Users of this
function should read L<perllocale>, whch provides a comprehensive
discussion of Perl locale handling, knowledge of which is necessary to
package locale;
-our $VERSION = '1.08';
+our $VERSION = '1.09';
use Config;
$Carp::Internal{ (__PACKAGE__) } = 1;
locale - Perl pragma to use or avoid POSIX locales for built-in operations
+=head1 WARNING
+
+DO NOT USE this pragma in scripts that have multiple
+L<threads|threads> active. The locale is not local to a single thread.
+Another thread may change the locale at any time, which could cause at a
+minimum that a given thread is operating in a locale it isn't expecting
+to be in. On some platforms, segfaults can also occur. The locale
+change need not be explicit; some operations cause perl to change the
+locale itself. You are vulnerable simply by having done a C<"use
+locale">.
+
=head1 SYNOPSIS
@x = sort @y; # Native-platform/Unicode code point sort order
=head2 The C<"use locale"> pragma
+WARNING! Do NOT use this pragma in scripts that have multiple
+L<threads|threads> active. The locale is not local to a single thread.
+Another thread may change the locale at any time, which could cause at a
+minimum that a given thread is operating in a locale it isn't expecting
+to be in. On some platforms, segfaults can also occur. The locale
+change need not be explicit; some operations cause perl to change the
+locale itself. You are vulnerable simply by having done a C<"use
+locale">.
+
By default, Perl itself (outside the L<POSIX> module)
ignores the current locale. The S<C<use locale>>
pragma tells Perl to use the current locale for some operations.
=head2 The setlocale function
+WARNING! Do NOT use this function in a L<thread|threads>. The locale
+will change in all other threads at the same time, and should your
+thread get paused by the operating system, and another started, that
+thread will not have the locale it is expecting. On some platforms,
+there can be a race leading to segfaults if two threads call this
+function nearly simultaneously.
+
You can switch locales as often as you wish at run time with the
C<POSIX::setlocale()> function:
# restore the old locale
setlocale(LC_CTYPE, $old_locale);
-This simultaneously affects all threads of the program, so it may be
-problematic to use locales in threaded applications except where there
-is a single locale applicable to all threads.
-
The first argument of C<setlocale()> gives the B<category>, the second the
B<locale>. The category tells in what aspect of data processing you
want to apply locale-specific rules. Category names are discussed in