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Perl 5 version 18.0 documentation
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locale - Perl pragma to use or avoid POSIX locales for built-in operations


  1. @x = sort @y; # Unicode sorting order
  2. {
  3. use locale;
  4. @x = sort @y; # Locale-defined sorting order
  5. }
  6. @x = sort @y; # Unicode sorting order again


This pragma tells the compiler to enable (or disable) the use of POSIX locales for built-in operations (for example, LC_CTYPE for regular expressions, LC_COLLATE for string comparison, and LC_NUMERIC for number formatting). Each "use locale" or "no locale" affects statements to the end of the enclosing BLOCK.

Starting in Perl 5.16, a hybrid mode for this pragma is available,

  1. use locale ':not_characters';

which enables only the portions of locales that don't affect the character set (that is, all except LC_COLLATE and LC_CTYPE). This is useful when mixing Unicode and locales, including UTF-8 locales.

  1. use locale ':not_characters';
  2. use open ":locale"; # Convert I/O to/from Unicode
  3. use POSIX qw(locale_h); # Import the LC_ALL constant
  4. setlocale(LC_ALL, ""); # Required for the next statement
  5. # to take effect
  6. printf "%.2f\n", 12345.67' # Locale-defined formatting
  7. @x = sort @y; # Unicode-defined sorting order.
  8. # (Note that you will get better
  9. # results using Unicode::Collate.)

See perllocale for more detailed information on how Perl supports locales.


If your system does not support locales, then loading this module will cause the program to die with a message:

  1. "Your vendor does not support locales, you cannot use the locale
  2. module."