explicit comparison function, because it uses C<cmp> by default.
B<Note:> C<eq> and C<ne> are unaffected by locale: they always
-perform a byte-by-byte comparison of their scalar operands. What's
+perform a char-by-char comparison of their scalar operands. What's
more, if C<cmp> finds that its operands are equal according to the
collation sequence specified by the current locale, it goes on to
-perform a byte-by-byte comparison, and only returns I<0> (equal) if the
-operands are bit-for-bit identical. If you really want to know whether
+perform a char-by-char comparison, and only returns I<0> (equal) if the
+operands are char-for-char identical. If you really want to know whether
two strings--which C<eq> and C<cmp> may consider different--are equal
as far as collation in the locale is concerned, see the discussion in
L<Category LC_COLLATE: Collation>.
=back
-C<LC_COLLATE>, C<LC_CTYPE>, and so on, are discussed further in L<LOCALE
-CATEGORIES>.
+C<LC_COLLATE>, C<LC_CTYPE>, and so on, are discussed further in
+L<LOCALE CATEGORIES>.
The default behavior is restored with the S<C<no locale>> pragma, or
upon reaching the end of block enclosing C<use locale>.
setenv LC_ALL en_US.ISO8859-1
+or if you have the "env" application you can do in any shell
+
+ env LC_ALL=en_US.ISO8859-1 perl ...
+
If you do not know what shell you have, consult your local
helpdesk or the equivalent.
the same. In this case, try running under a locale
that you can list and which somehow matches what you tried. The
rules for matching locale names are a bit vague because
-standardization is weak in this area. See again the L<Finding
-locales> about general rules.
+standardization is weak in this area. See again the
+L<Finding locales> about general rules.
=head2 Fixing system locale configuration
localeconv() takes no arguments, and returns B<a reference to> a hash.
The keys of this hash are variable names for formatting, such as
C<decimal_point> and C<thousands_sep>. The values are the
-corresponding, er, values. See L<POSIX (3)/localeconv> for a longer
+corresponding, er, values. See L<POSIX/localeconv> for a longer
example listing the categories an implementation might be expected to
provide; some provide more and others fewer. You don't need an
explicit C<use locale>, because localeconv() always observes the
}
print "\n";
+=head2 I18N::Langinfo
+
+Another interface for querying locale-dependent information is the
+I18N::Langinfo::langinfo() function, available at least in UNIX-like
+systems and VMS.
+
+The following example will import the langinfo() function itself and
+three constants to be used as arguments to langinfo(): a constant for
+the abbreviated first day of the week (the numbering starts from
+Sunday = 1) and two more constants for the affirmative and negative
+answers for a yes/no question in the current locale.
+
+ use I18N::Langinfo qw(langinfo ABDAY_1 YESSTR NOSTR);
+
+ my ($abday_1, $yesstr, $nostr) = map { langinfo } qw(ABDAY_1 YESSTR NOSTR);
+
+ print "$abday_1? [$yesstr/$nostr] ";
+
+In other words, in the "C" (or English) locale the above will probably
+print something like:
+
+ Sun? [yes/no]
+
+See L<I18N::Langinfo> for more information.
+
=head1 LOCALE CATEGORIES
The following subsections describe basic locale categories. Beyond these,
if you "use locale".
A B C D E a b c d e
- A a B b C c D d D e
+ A a B b C c D d E e
a A b B c C d D e E
a b c d e A B C D E
characters are in the current locale, in that locale's order:
use locale;
- print +(sort grep /\w/, map { chr() } 0..255), "\n";
+ print +(sort grep /\w/, map { chr } 0..255), "\n";
Compare this with the characters that you see and their order if you
state explicitly that the locale should be ignored:
no locale;
- print +(sort grep /\w/, map { chr() } 0..255), "\n";
+ print +(sort grep /\w/, map { chr } 0..255), "\n";
This machine-native collation (which is what you get unless S<C<use
locale>> has appeared earlier in the same block) must be used for
As noted in L<USING LOCALES>, C<cmp> compares according to the current
collation locale when C<use locale> is in effect, but falls back to a
-byte-by-byte comparison for strings that the locale says are equal. You
+char-by-char comparison for strings that the locale says are equal. You
can use POSIX::strcoll() if you don't want this fall-back:
use POSIX qw(strcoll);
if $xfrm_string eq strxfrm("mixed-case string");
strxfrm() takes a string and maps it into a transformed string for use
-in byte-by-byte comparisons against other transformed strings during
+in char-by-char comparisons against other transformed strings during
collation. "Under the hood", locale-affected Perl comparison operators
-call strxfrm() for both operands, then do a byte-by-byte
+call strxfrm() for both operands, then do a char-by-char
comparison of the transformed strings. By calling strxfrm() explicitly
and using a non locale-affected comparison, the example attempts to save
a couple of transformations. But in fact, it doesn't save anything: Perl
These functions aren't aware of such niceties as thousands separation and
so on. (See L<The localeconv function> if you care about these things.)
-Output produced by print() is B<never> affected by the
-current locale: it is independent of whether C<use locale> or C<no
-locale> is in effect, and corresponds to what you'd get from printf()
-in the "C" locale. The same is true for Perl's internal conversions
-between numeric and string formats:
+Output produced by print() is also affected by the current locale: it
+depends on whether C<use locale> or C<no locale> is in effect, and
+corresponds to what you'd get from printf() in the "C" locale. The
+same is true for Perl's internal conversions between numeric and
+string formats:
use POSIX qw(strtod);
use locale;
$n = 5/2; # Assign numeric 2.5 to $n
- $a = " $n"; # Locale-independent conversion to string
+ $a = " $n"; # Locale-dependent conversion to string
- print "half five is $n\n"; # Locale-independent output
+ print "half five is $n\n"; # Locale-dependent output
printf "half five is %g\n", $n; # Locale-dependent output
print "DECIMAL POINT IS COMMA\n"
if $n == (strtod("2,5"))[0]; # Locale-dependent conversion
+See also L<I18N::Langinfo> and C<RADIXCHAR>.
+
=head2 Category LC_MONETARY: Formatting of monetary amounts
The C standard defines the C<LC_MONETARY> category, but no function
that is affected by its contents. (Those with experience of standards
committees will recognize that the working group decided to punt on the
issue.) Consequently, Perl takes no notice of it. If you really want
-to use C<LC_MONETARY>, you can query its contents--see L<The localeconv
-function>--and use the information that it returns in your application's
-own formatting of currency amounts. However, you may well find that
-the information, voluminous and complex though it may be, still does not
-quite meet your requirements: currency formatting is a hard nut to crack.
+to use C<LC_MONETARY>, you can query its contents--see
+L<The localeconv function>--and use the information that it returns in your
+application's own formatting of currency amounts. However, you may well
+find that the information, voluminous and complex though it may be, still
+does not quite meet your requirements: currency formatting is a hard nut
+to crack.
+
+See also L<I18N::Langinfo> and C<CRNCYSTR>.
=head2 LC_TIME
exists only to generate locale-dependent results, strftime() always
obeys the current C<LC_TIME> locale.
+See also L<I18N::Langinfo> and C<ABDAY_1>..C<ABDAY_7>, C<DAY_1>..C<DAY_7>,
+C<ABMON_1>..C<ABMON_12>, and C<ABMON_1>..C<ABMON_12>.
+
=head2 Other categories
The remaining locale category, C<LC_MESSAGES> (possibly supplemented
=item *
-Some systems are broken in that they allow the "C" locale to be
-overridden by users. If the decimal point character in the
-C<LC_NUMERIC> category of the "C" locale is surreptitiously changed
-from a dot to a comma, C<sprintf("%g", 0.123456e3)> produces a
-string result of "123,456". Many people would interpret this as
-one hundred and twenty-three thousand, four hundred and fifty-six.
-
-=item *
-
A sneaky C<LC_COLLATE> locale could result in the names of students with
"D" grades appearing ahead of those with "A"s.
=over 4
-=item B<Comparison operators> (C<lt>, C<le>, C<ge>, C<gt> and C<cmp>):
+=item *
+
+B<Comparison operators> (C<lt>, C<le>, C<ge>, C<gt> and C<cmp>):
Scalar true/false (or less/equal/greater) result is never tainted.
-=item B<Case-mapping interpolation> (with C<\l>, C<\L>, C<\u> or C<\U>)
+=item *
+
+B<Case-mapping interpolation> (with C<\l>, C<\L>, C<\u> or C<\U>)
Result string containing interpolated material is tainted if
C<use locale> is in effect.
-=item B<Matching operator> (C<m//>):
+=item *
+
+B<Matching operator> (C<m//>):
Scalar true/false result never tainted.
C<use locale> is in effect and the regular expression contains C<\w>,
C<\W>, C<\s>, or C<\S>.
-=item B<Substitution operator> (C<s///>):
+=item *
+
+B<Substitution operator> (C<s///>):
Has the same behavior as the match operator. Also, the left
operand of C<=~> becomes tainted when C<use locale> in effect
expression match involving C<\w>, C<\W>, C<\s>, or C<\S>; or of
case-mapping with C<\l>, C<\L>,C<\u> or C<\U>.
-=item B<Output formatting functions> (printf() and write()):
+=item *
+
+B<Output formatting functions> (printf() and write()):
+
+Results are never tainted because otherwise even output from print,
+for example C<print(1/7)>, should be tainted if C<use locale> is in
+effect.
-Success/failure result is never tainted.
+=item *
-=item B<Case-mapping functions> (lc(), lcfirst(), uc(), ucfirst()):
+B<Case-mapping functions> (lc(), lcfirst(), uc(), ucfirst()):
Results are tainted if C<use locale> is in effect.
-=item B<POSIX locale-dependent functions> (localeconv(), strcoll(),
+=item *
+
+B<POSIX locale-dependent functions> (localeconv(), strcoll(),
strftime(), strxfrm()):
Results are never tainted.
-=item B<POSIX character class tests> (isalnum(), isalpha(), isdigit(),
+=item *
+
+B<POSIX character class tests> (isalnum(), isalpha(), isdigit(),
isgraph(), islower(), isprint(), ispunct(), isspace(), isupper(),
isxdigit()):
=head2 Freely available locale definitions
There is a large collection of locale definitions at
-C<ftp://dkuug.dk/i18n/WG15-collection>. You should be aware that it is
+ftp://dkuug.dk/i18n/WG15-collection . You should be aware that it is
unsupported, and is not claimed to be fit for any purpose. If your
system allows installation of arbitrary locales, you may find the
definitions useful as they are, or as a basis for the development of
into bankers, bikers, gamers, and so on. But, for now, it's the only
standard we've got. This may be construed as a bug.
+=head1 Unicode and UTF-8
+
+The support of Unicode is new starting from Perl version 5.6, and
+more fully implemented in the version 5.8. See L<perluniintro> and
+L<perlunicode> for more details.
+
+Usually locale settings and Unicode do not affect each other, but
+there are exceptions, see L<perlunicode/Locales> for examples.
+
=head1 BUGS
=head2 Broken systems
=head1 SEE ALSO
-L<POSIX (3)/isalnum>, L<POSIX (3)/isalpha>, L<POSIX (3)/isdigit>,
-L<POSIX (3)/isgraph>, L<POSIX (3)/islower>, L<POSIX (3)/isprint>,
-L<POSIX (3)/ispunct>, L<POSIX (3)/isspace>, L<POSIX (3)/isupper>,
-L<POSIX (3)/isxdigit>, L<POSIX (3)/localeconv>, L<POSIX (3)/setlocale>,
-L<POSIX (3)/strcoll>, L<POSIX (3)/strftime>, L<POSIX (3)/strtod>,
-L<POSIX (3)/strxfrm>.
+L<I18N::Langinfo>, L<perluniintro>, L<perlunicode>, L<open>,
+L<POSIX/isalnum>, L<POSIX/isalpha>,
+L<POSIX/isdigit>, L<POSIX/isgraph>, L<POSIX/islower>,
+L<POSIX/isprint>, L<POSIX/ispunct>, L<POSIX/isspace>,
+L<POSIX/isupper>, L<POSIX/isxdigit>, L<POSIX/localeconv>,
+L<POSIX/setlocale>, L<POSIX/strcoll>, L<POSIX/strftime>,
+L<POSIX/strtod>, L<POSIX/strxfrm>.
=head1 HISTORY
https://perl5.git.perl.org / perl5.git / blobdiff