X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/98a6f11e5caa62333286d697f0f5df32e778e17a..de108802002fd7758d661282179febed13a1e304:/pod/perllocale.pod diff --git a/pod/perllocale.pod b/pod/perllocale.pod index 0447b26..e2ea04d 100644 --- a/pod/perllocale.pod +++ b/pod/perllocale.pod @@ -99,11 +99,11 @@ C. sort() is also affected if used without an explicit comparison function, because it uses C by default. B C and C 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 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 and C may consider different--are equal as far as collation in the locale is concerned, see the discussion in L. @@ -124,8 +124,8 @@ B (strftime()) uses C. =back -C, C, and so on, are discussed further in L. +C, C, and so on, are discussed further in +L. The default behavior is restored with the S> pragma, or upon reaching the end of block enclosing C. @@ -289,7 +289,7 @@ than the PERL_BADLANG approach, but setting LC_ALL (or other locale variables) may affect other programs as well, not just Perl. In particular, external programs run from within Perl will see these changes. If you make the new settings permanent (read on), all -programs you run see the changes. See L for for +programs you run see the changes. See L for the full list of relevant environment variables and L for their effects in Perl. Effects in other programs are easily deducible. For example, the variable LC_COLLATE may well affect @@ -309,7 +309,11 @@ discussed above. We decided to try that instead of the above faulty locale "En_US"--and in Cshish shells (B, B) 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. @@ -332,9 +336,9 @@ Second, if using the listed commands you see something B (prefix matches do not count and case usually counts) like "En_US" without the quotes, then you should be okay because you are using a locale name that should be installed and available in your system. -In this case, see L. +In this case, see L. -=head2 Permanently fixing your locale configuration +=head2 Permanently fixing your system's locale configuration This is when you see something like: @@ -348,8 +352,8 @@ commands. You may see things like "en_US.ISO8859-1", but that isn't 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 about general rules. +standardization is weak in this area. See again the +L about general rules. =head2 Fixing system locale configuration @@ -381,7 +385,7 @@ with a single parameter--see L.) localeconv() takes no arguments, and returns B a hash. The keys of this hash are variable names for formatting, such as C and C. The values are the -corresponding, er, values. See L for a longer +corresponding, er, values. See L 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, because localeconv() always observes the @@ -427,6 +431,31 @@ parameters as integers correctly formatted in the current locale: } 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 for more information. + =head1 LOCALE CATEGORIES The following subsections describe basic locale categories. Beyond these, @@ -445,21 +474,21 @@ The following collations all make sense and you may meet any of them 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 -Here is a code snippet to tell what alphanumeric +Here is a code snippet to tell what "word" 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> has appeared earlier in the same block) must be used for @@ -468,7 +497,7 @@ first example is useful for natural text. As noted in L, C compares according to the current collation locale when C 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); @@ -493,9 +522,9 @@ efficiency by using POSIX::strxfrm() in conjunction with C: 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 @@ -518,8 +547,9 @@ results, and so always obey the current C locale. In the scope of S>, Perl obeys the C locale setting. This controls the application's notion of which characters are alphabetic. This affects Perl's C<\w> regular expression metanotation, -which stands for alphanumeric characters--that is, alphabetic and -numeric characters. (Consult L for more information about +which stands for alphanumeric characters--that is, alphabetic, +numeric, and including other special characters such as the underscore or +hyphen. (Consult L for more information about regular expressions.) Thanks to C, depending on your locale setting, characters like 'E', 'E', 'E', and 'E' may be understood as C<\w> characters. @@ -553,37 +583,42 @@ change the character used for the decimal point--perhaps from '.' to ','. These functions aren't aware of such niceties as thousands separation and so on. (See L if you care about these things.) -Output produced by print() is B affected by the -current locale: it is independent of whether C or C 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 or C 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 $n == (strtod("2,5"))[0]; # Locale-dependent conversion +See also L and C. + =head2 Category LC_MONETARY: Formatting of monetary amounts The C standard defines the C category, but no function that is affected by its contents. (Those with experience of standards committees will recognize that the working group decided to punt on the issue.) Consequently, Perl takes no notice of it. If you really want -to use C, you can query its contents--see L--and use the information that it returns in your application's -own formatting of currency amounts. However, you may well find that -the information, voluminous and complex though it may be, still does not -quite meet your requirements: currency formatting is a hard nut to crack. +to use C, you can query its contents--see +L--and use the information that it returns in your +application's own formatting of currency amounts. However, you may well +find that the information, voluminous and complex though it may be, still +does not quite meet your requirements: currency formatting is a hard nut +to crack. + +See also L and C. =head2 LC_TIME @@ -604,6 +639,9 @@ Note: C isn't needed in this example: as a function that exists only to generate locale-dependent results, strftime() always obeys the current C locale. +See also L and C..C, C..C, +C..C, and C..C. + =head2 Other categories The remaining locale category, C (possibly supplemented @@ -613,7 +651,7 @@ called by extensions outside the standard Perl distribution and by the operating system and its utilities. Note especially that the string value of C<$!> and the error messages given by external utilities may be changed by C. If you want to have portable error -codes, use the Errno extension. +codes, use C<%!>. See L. =head1 SECURITY @@ -641,14 +679,6 @@ case-mapping table is in effect. =item * -If the decimal point character in the C locale is -surreptitiously changed from a dot to a comma, C 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 locale could result in the names of students with "D" grades appearing ahead of those with "A"s. @@ -684,16 +714,22 @@ the locale: =over 4 -=item B (C, C, C, C and C): +=item * + +B (C, C, C, C and C): Scalar true/false (or less/equal/greater) result is never tainted. -=item B (with C<\l>, C<\L>, C<\u> or C<\U>) +=item * + +B (with C<\l>, C<\L>, C<\u> or C<\U>) Result string containing interpolated material is tainted if C is in effect. -=item B (C): +=item * + +B (C): Scalar true/false result never tainted. @@ -706,7 +742,9 @@ expression contains C<\w> (to match an alphanumeric character), C<\W> C is in effect and the regular expression contains C<\w>, C<\W>, C<\s>, or C<\S>. -=item B (C): +=item * + +B (C): Has the same behavior as the match operator. Also, the left operand of C<=~> becomes tainted when C in effect @@ -714,24 +752,30 @@ if modified as a result of a substitution based on a regular 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 (sprintf()): +=item * -Result is tainted if C is in effect. +B (printf() and write()): -=item B (printf() and write()): +Results are never tainted because otherwise even output from print, +for example C, should be tainted if C is in +effect. -Success/failure result is never tainted. +=item * -=item B (lc(), lcfirst(), uc(), ucfirst()): +B (lc(), lcfirst(), uc(), ucfirst()): Results are tainted if C is in effect. -=item B (localeconv(), strcoll(), +=item * + +B (localeconv(), strcoll(), strftime(), strxfrm()): Results are never tainted. -=item B (isalnum(), isalpha(), isdigit(), +=item * + +B (isalnum(), isalpha(), isdigit(), isgraph(), islower(), isprint(), ispunct(), isspace(), isupper(), isxdigit()): @@ -917,7 +961,7 @@ structure. =head2 Freely available locale definitions There is a large collection of locale definitions at -C. 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 @@ -941,6 +985,15 @@ nations, when we all know that the world can equally well be divided 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 and +L for more details. + +Usually locale settings and Unicode do not affect each other, but +there are exceptions, see L for examples. + =head1 BUGS =head2 Broken systems @@ -949,44 +1002,20 @@ In certain systems, the operating system's locale support is broken and cannot be fixed or used by Perl. Such deficiencies can and will result in mysterious hangs and/or Perl core dumps when the C is in effect. When confronted with such a system, -please report in excruciating detail to >, and +please report in excruciating detail to >, and complain to your vendor: bug fixes may exist for these problems in your operating system. Sometimes such bug fixes are called an operating system upgrade. =head1 SEE ALSO -L - -L - -L - -L - -L - -L, - -L - -L - -L, - -L - -L - -L, - -L - -L - -L, - -L +L, L, L, L, +L, L, +L, L, L, +L, L, L, +L, L, L, +L, L, L, +L, L. =head1 HISTORY