A locale is the definition of the subset of a user's environment that depends on language and cultural conventions. It is made up from one or more categories. Each category is identified by its name and controls specific aspects of the behavior of components of the system. Category names correspond to the following environment variable names:
The standard utilities in the Shell and Utilities volume of IEEE Std 1003.1-2001 shall base their behavior on the current locale, as defined in the ENVIRONMENT VARIABLES section for each utility. The behavior of some of the C-language functions defined in the System Interfaces volume of IEEE Std 1003.1-2001 shall also be modified based on the current locale, as defined by the last call to setlocale().
Locales other than those supplied by the implementation can be created via the localedef utility, provided that the _POSIX2_LOCALEDEF symbol is defined on the system. Even if localedef is not provided, all implementations conforming to the System Interfaces volume of IEEE Std 1003.1-2001 shall provide one or more locales that behave as described in this chapter. The input to the utility is described in Locale Definition. The value that is used to specify a locale when using environment variables shall be the string specified as the name operand to the localedef utility when the locale was created. The strings "C" and "POSIX" are reserved as identifiers for the POSIX locale (see POSIX Locale). When the value of a locale environment variable begins with a slash ( '/' ), it shall be interpreted as the pathname of the locale definition; the type of file (regular, directory, and so on) used to store the locale definition is implementation-defined. If the value does not begin with a slash, the mechanism used to locate the locale is implementation-defined.
If different character sets are used by the locale categories, the results achieved by an application utilizing these categories are undefined. Likewise, if different codesets are used for the data being processed by interfaces whose behavior is dependent on the current locale, or the codeset is different from the codeset assumed when the locale was created, the result is also undefined.
Applications can select the desired locale by invoking the setlocale() function (or equivalent) with the appropriate value. If the function is invoked with an empty string, such as:
setlocale(LC_ALL, "");
the value of the corresponding environment variable is used. If the environment variable is unset or is set to the empty string, the implementation shall set the appropriate environment as defined in Environment Variables.
Conforming systems shall provide a POSIX locale, also known as the C locale. The behavior of standard utilities and functions in the POSIX locale shall be as if the locale was defined via the localedef utility with input data from the POSIX locale tables in Locale Definition.
The tables in Locale Definition describe the characteristics and behavior of the POSIX locale for data consisting entirely of characters from the portable character set and the control character set. For other characters, the behavior is unspecified. For C-language programs, the POSIX locale shall be the default locale when the setlocale() function is not called.
The POSIX locale can be specified by assigning to the appropriate environment variables the values "C" or "POSIX".
All implementations shall define a locale as the default locale, to be invoked when no environment variables are set, or set to the empty string. This default locale can be the POSIX locale or any other implementation-defined locale. Some implementations may provide facilities for local installation administrators to set the default locale, customizing it for each location. IEEE Std 1003.1-2001 does not require such a facility.
The capability to specify additional locales to those provided by an implementation is optional, denoted by the _POSIX2_LOCALEDEF symbol. If the option is not supported, only implementation-supplied locales are available. Such locales shall be documented using the format specified in this section.
Locales can be described with the file format presented in this section. The file format is that accepted by the localedef utility. For the purposes of this section, the file is referred to as the "locale definition file", but no locales shall be affected by this file unless it is processed by localedef or some similar mechanism. Any requirements in this section imposed upon the utility shall apply to localedef or to any other similar utility used to install locale information using the locale definition file format described here.
The locale definition file shall contain one or more locale category source definitions, and shall not contain more than one definition for the same locale category. If the file contains source definitions for more than one category, implementation-defined categories, if present, shall appear after the categories defined by General. A category source definition contains either the definition of a category or a copy directive. For a description of the copy directive, see localedef. In the event that some of the information for a locale category, as specified in this volume of IEEE Std 1003.1-2001, is missing from the locale source definition, the behavior of that category, if it is referenced, is unspecified.
A category source definition shall consist of a category header, a category body, and a category trailer. A category header shall consist of the character string naming of the category, beginning with the characters LC_ . The category trailer shall consist of the string "END", followed by one or more <blank>s and the string used in the corresponding category header.
The category body shall consist of one or more lines of text. Each line shall contain an identifier, optionally followed by one or more operands. Identifiers shall be either keywords, identifying a particular locale element, or collating elements. In addition to the keywords defined in this volume of IEEE Std 1003.1-2001, the source can contain implementation-defined keywords. Each keyword within a locale shall have a unique name (that is, two categories cannot have a commonly-named keyword); no keyword shall start with the characters LC_ . Identifiers shall be separated from the operands by one or more <blank>s.
Operands shall be characters, collating elements, or strings of characters. Strings shall be enclosed in double-quotes. Literal double-quotes within strings shall be preceded by the <escape character>, described below. When a keyword is followed by more than one operand, the operands shall be separated by semicolons; <blank>s shall be allowed both before and after a semicolon.
The first category header in the file can be preceded by a line modifying the comment character. It shall have the following format, starting in column 1:
"comment_char %c\n", <comment character>
The comment character shall default to the number sign ( '#' ). Blank lines and lines containing the <comment character> in the first position shall be ignored.
The first category header in the file can be preceded by a line modifying the escape character to be used in the file. It shall have the following format, starting in column 1:
"escape_char %c\n", <escape character>
The escape character shall default to backslash, which is the character used in all examples shown in this volume of IEEE Std 1003.1-2001.
A line can be continued by placing an escape character as the last character on the line; this continuation character shall be discarded from the input. Although the implementation need not accept any one portion of a continued line with a length exceeding {LINE_MAX} bytes, it shall place no limits on the accumulated length of the continued line. Comment lines shall not be continued on a subsequent line using an escaped <newline>.
Individual characters, characters in strings, and collating elements shall be represented using symbolic names, as defined below. In addition, characters can be represented using the characters themselves or as octal, hexadecimal, or decimal constants. When non-symbolic notation is used, the resultant locale definitions are in many cases not portable between systems. The left angle bracket ( '<' ) is a reserved symbol, denoting the start of a symbolic name; when used to represent itself it shall be preceded by the escape character. The following rules apply to character representation:
A character can be represented via a symbolic name, enclosed within angle brackets '<' and '>'. The symbolic name, including the angle brackets, shall exactly match a symbolic name defined in the charmap file specified via the localedef -f option, and it shall be replaced by a character value determined from the value associated with the symbolic name in the charmap file. The use of a symbolic name not found in the charmap file shall constitute an error, unless the category is LC_CTYPE or LC_COLLATE , in which case it shall constitute a warning condition (see localedef for a description of actions resulting from errors and warnings). The specification of a symbolic name in a collating-element or collating-symbol section that duplicates a symbolic name in the charmap file (if present) shall be an error. Use of the escape character or a right angle bracket within a symbolic name is invalid unless the character is preceded by the escape character.
For example:
<c>;<c-cedilla> "<M><a><y>"
A character in the portable character set can be represented by the character itself, in which case the value of the character is implementation-defined. (Implementations may allow other characters to be represented as themselves, but such locale definitions are not portable.) Within a string, the double-quote character, the escape character, and the right angle bracket character shall be escaped (preceded by the escape character) to be interpreted as the character itself. Outside strings, the characters:
, ; < > escape_char
shall be escaped to be interpreted as the character itself.
For example:
c "May"
A character can be represented as an octal constant. An octal constant shall be specified as the escape character followed by two or three octal digits. Each constant shall represent a byte value. Multi-byte values can be represented by concatenated constants specified in byte order with the last constant specifying the least significant byte of the character.
For example:
\143;\347;\143\150 "\115\141\171"
A character can be represented as a hexadecimal constant. A hexadecimal constant shall be specified as the escape character followed by an 'x' followed by two hexadecimal digits. Each constant shall represent a byte value. Multi-byte values can be represented by concatenated constants specified in byte order with the last constant specifying the least significant byte of the character.
For example:
\x63;\xe7;\x63\x68 "\x4d\x61\x79"
A character can be represented as a decimal constant. A decimal constant shall be specified as the escape character followed by a 'd' followed by two or three decimal digits. Each constant represents a byte value. Multi-byte values can be represented by concatenated constants specified in byte order with the last constant specifying the least significant byte of the character.
For example:
\d99;\d231;\d99\d104 "\d77\d97\d121"
Implementations may accept single-digit octal, decimal, or hexadecimal constants following the escape character. Only characters existing in the character set for which the locale definition is created shall be specified, whether using symbolic names, the characters themselves, or octal, decimal, or hexadecimal constants. If a charmap file is present, only characters defined in the charmap can be specified using octal, decimal, or hexadecimal constants. Symbolic names not present in the charmap file can be specified and shall be ignored, as specified under item 1 above.
The LC_CTYPE category shall define character classification, case conversion, and other character attributes. In addition, a series of characters can be represented by three adjacent periods representing an ellipsis symbol ( "..." ). The ellipsis specification shall be interpreted as meaning that all values between the values preceding and following it represent valid characters. The ellipsis specification shall be valid only within a single encoded character set; that is, within a group of characters of the same size. An ellipsis shall be interpreted as including in the list all characters with an encoded value higher than the encoded value of the character preceding the ellipsis and lower than the encoded value of the character following the ellipsis.
For example:
\x30;...;\x39;
includes in the character class all characters with encoded values between the endpoints.
The following keywords shall be recognized. In the descriptions, the term "automatically included" means that it shall not be an error either to include or omit any of the referenced characters; the implementation provides them if missing (even if the entire keyword is missing) and accepts them silently if present. When the implementation automatically includes a missing character, it shall have an encoded value dependent on the charmap file in effect (see the description of the localedef -f option); otherwise, it shall have a value derived from an implementation-defined character mapping.
The character classes digit, xdigit, lower, upper, and space have a set of automatically included characters. These only need to be specified if the character values (that is, encoding) differ from the implementation default values. It is not possible to define a locale without these automatically included characters unless some implementation extension is used to prevent their inclusion. Such a definition would not be a proper superset of the C or POSIX locale and, thus, it might not be possible for conforming applications to work properly.
In the POSIX locale, the 26 uppercase letters shall be included:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
In a locale definition file, no character specified for the keywords cntrl, digit, punct, or space shall be specified. The uppercase letters <A> to <Z>, as defined in Character Set Description File (the portable character set), are automatically included in this class.
In the POSIX locale, the 26 lowercase letters shall be included:
a b c d e f g h i j k l m n o p q r s t u v w x y z
In a locale definition file, no character specified for the keywords cntrl, digit, punct, or space shall be specified. The lowercase letters <a> to <z> of the portable character set are automatically included in this class.
In the POSIX locale, all characters in the classes upper and lower shall be included.
In a locale definition file, no character specified for the keywords cntrl, digit, punct, or space shall be specified. Characters classified as either upper or lower are automatically included in this class.
In the POSIX locale, only:
0 1 2 3 4 5 6 7 8 9
shall be included.
In a locale definition file, only the digits <zero>, <one>, <two>, <three>, <four>, <five>, <six>, <seven>, <eight>, and <nine> shall be specified, and in contiguous ascending sequence by numerical value. The digits <zero> to <nine> of the portable character set are automatically included in this class.
In the POSIX locale, at a minimum, the <space>, <form-feed>, <newline>, <carriage-return>, <tab>, and <vertical-tab> shall be included.
In a locale definition file, no character specified for the keywords upper, lower, alpha, digit, graph, or xdigit shall be specified. The <space>, <form-feed>, <newline>, <carriage-return>, <tab>, and <vertical-tab> of the portable character set, and any characters included in the class blank are automatically included in this class.
In the POSIX locale, no characters in classes alpha or print shall be included.
In a locale definition file, no character specified for the keywords upper, lower, alpha, digit, punct, graph, print, or xdigit shall be specified.
In the POSIX locale, neither the <space> nor any characters in classes alpha, digit, or cntrl shall be included.
In a locale definition file, no character specified for the keywords upper, lower, alpha, digit, cntrl, xdigit, or as the <space> shall be specified.
In the POSIX locale, all characters in classes alpha, digit, and punct shall be included; no characters in class cntrl shall be included.
In a locale definition file, characters specified for the keywords upper, lower, alpha, digit, xdigit, and punct are automatically included in this class. No character specified for the keyword cntrl shall be specified.
In the POSIX locale, all characters in class graph shall be included; no characters in class cntrl shall be included.
In a locale definition file, characters specified for the keywords upper, lower, alpha, digit, xdigit, punct, graph, and the <space> are automatically included in this class. No character specified for the keyword cntrl shall be specified.
In the POSIX locale, only:
0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f
shall be included.
In a locale definition file, only the characters defined for the class digit shall be specified, in contiguous ascending sequence by numerical value, followed by one or more sets of six characters representing the hexadecimal digits 10 to 15 inclusive, with each set in ascending order (for example, <A>, <B>, <C>, <D>, <E>, <F>, <a>, <b>, <c>, <d>, <e>, <f>). The digits <zero> to <nine>, the uppercase letters <A> to <F>, and the lowercase letters <a> to <f> of the portable character set are automatically included in this class.
In the POSIX locale, only the <space> and <tab> shall be included.
In a locale definition file, the <space> and <tab> are automatically included in this class.
If a class name is defined by a charclass keyword, but no characters are subsequently assigned to it, this is not an error; it represents a class without any characters belonging to it.
The charclass-name can be used as the property argument to the wctype() function, in regular expression and shell pattern-matching bracket expressions, and by the tr command.
In the POSIX locale, at a minimum, the 26 lowercase characters:
a b c d e f g h i j k l m n o p q r s t u v w x y z
shall be mapped to the corresponding 26 uppercase characters:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
In a locale definition file, the operand shall consist of character pairs, separated by semicolons. The characters in each character pair shall be separated by a comma and the pair enclosed by parentheses. The first character in each pair is the lowercase letter, the second the corresponding uppercase letter. Only characters specified for the keywords lower and upper shall be specified. The lowercase letters <a> to <z>, and their corresponding uppercase letters <A> to <Z>, of the portable character set are automatically included in this mapping, but only when the toupper keyword is omitted from the locale definition.
In the POSIX locale, at a minimum, the 26 uppercase characters:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
shall be mapped to the corresponding 26 lowercase characters:
a b c d e f g h i j k l m n o p q r s t u v w x y z
In a locale definition file, the operand shall consist of character pairs, separated by semicolons. The characters in each character pair shall be separated by a comma and the pair enclosed by parentheses. The first character in each pair is the uppercase letter, the second the corresponding lowercase letter. Only characters specified for the keywords lower and upper shall be specified. If the tolower keyword is omitted from the locale definition, the mapping is the reverse mapping of the one specified for toupper.
The following table shows the character class combinations allowed:
|
|
Can Also Belong To |
|
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
_ |
|
||||||||||
|
In Class |
upper |
lower |
alpha |
digit |
space |
cntrl |
punct |
graph |
|
xdigit |
blank |
|
|
upper |
|
- |
A |
x |
x |
x |
x |
A |
A |
- |
x |
|
|
lower |
- |
A |
x |
x |
x |
x |
A |
A |
- |
x |
|
|
|
alpha |
- |
- |
x |
x |
x |
x |
A |
A |
- |
x |
|
|
|
digit |
x |
x |
x |
x |
x |
x |
A |
A |
A |
x |
|
|
|
space |
x |
x |
x |
x |
- |
* |
* |
* |
x |
- |
|
|
|
cntrl |
x |
x |
x |
x |
- |
x |
x |
x |
x |
- |
|
|
|
punct |
x |
x |
x |
x |
- |
x |
A |
A |
x |
- |
|
|
|
graph |
- |
- |
- |
- |
- |
x |
- |
A |
- |
- |
|
|
|
|
- |
- |
- |
- |
- |
x |
- |
- |
- |
- |
|
|
|
xdigit |
- |
- |
- |
- |
x |
x |
x |
A |
A |
x |
|
|
|
blank |
x |
x |
x |
x |
A |
- |
* |
* |
* |
x |
|
|
Explanation of codes:
The <space>, which is part of the space and blank classes, cannot belong to punct or graph, but shall automatically belong to the print class. Other space or blank characters can be classified as any of punct, graph, or print.
The character classifications for the POSIX locale follow; the code listing depicts the localedef input, and the table represents the same information, sorted by character.
LC_CTYPE
# The following is the POSIX locale LC_CTYPE.
# "alpha" is by default "upper" and "lower"
# "alnum" is by definition "alpha" and "digit"
# "print" is by default "alnum", "punct", and the <space>
# "graph" is by default "alnum" and "punct"
#
upper <A>;<B>;<C>;<D>;<E>;<F>;<G>;<H>;<I>;<J>;<K>;<L>;<M>;\
<N>;<O>;<P>;<Q>;<R>;<S>;<T>;<U>;<V>;<W>;<X>;<Y>;<Z>
#
lower <a>;<b>;<c>;<d>;<e>;<f>;<g>;<h>;<i>;<j>;<k>;<l>;<m>;\
<n>;<o>;<p>;<q>;<r>;<s>;<t>;<u>;<v>;<w>;<x>;<y>;<z>
#
digit <zero>;<one>;<two>;<three>;<four>;<five>;<six>;\
<seven>;<eight>;<nine>
#
space <tab>;<newline>;<vertical-tab>;<form-feed>;\
<carriage-return>;<space>
#
cntrl <alert>;<backspace>;<tab>;<newline>;<vertical-tab>;\
<form-feed>;<carriage-return>;\
<NUL>;<SOH>;<STX>;<ETX>;<EOT>;<ENQ>;<ACK>;<SO>;\
<SI>;<DLE>;<DC1>;<DC2>;<DC3>;<DC4>;<NAK>;<SYN>;\
<ETB>;<CAN>;<EM>;<SUB>;<ESC>;<IS4>;<IS3>;<IS2>;\
<IS1>;<DEL>
#
punct <exclamation-mark>;<quotation-mark>;<number-sign>;\
<dollar-sign>;<percent-sign>;<ampersand>;<apostrophe>;\
<left-parenthesis>;<right-parenthesis>;<asterisk>;\
<plus-sign>;<comma>;<hyphen>;<period>;<slash>;\
<colon>;<semicolon>;<less-than-sign>;<equals-sign>;\
<greater-than-sign>;<question-mark>;<commercial-at>;\
<left-square-bracket>;<backslash>;<right-square-bracket>;\
<circumflex>;<underscore>;<grave-accent>;<left-curly-bracket>;\
<vertical-line>;<right-curly-bracket>;<tilde>
#
xdigit <zero>;<one>;<two>;<three>;<four>;<five>;<six>;<seven>;\
<eight>;<nine>;<A>;<B>;<C>;<D>;<E>;<F>;<a>;<b>;<c>;<d>;<e>;<f>
#
blank <space>;<tab>
#
toupper (<a>,<A>);(<b>,<B>);(<c>,<C>);(<d>,<D>);(<e>,<E>);\
(<f>,<F>);(<g>,<G>);(<h>,<H>);(<i>,<I>);(<j>,<J>);\
(<k>,<K>);(<l>,<L>);(<m>,<M>);(<n>,<N>);(<o>,<O>);\
(<p>,<P>);(<q>,<Q>);(<r>,<R>);(<s>,<S>);(<t>,<T>);\
(<u>,<U>);(<v>,<V>);(<w>,<W>);(<x>,<X>);(<y>,<Y>);(<z>,<Z>)
#
tolower (<A>,<a>);(<B>,<b>);(<C>,<c>);(<D>,<d>);(<E>,<e>);\
(<F>,<f>);(<G>,<g>);(<H>,<h>);(<I>,<i>);(<J>,<j>);\
(<K>,<k>);(<L>,<l>);(<M>,<m>);(<N>,<n>);(<O>,<o>);\
(<P>,<p>);(<Q>,<q>);(<R>,<r>);(<S>,<s>);(<T>,<t>);\
(<U>,<u>);(<V>,<v>);(<W>,<w>);(<X>,<x>);(<Y>,<y>);(<Z>,<z>)
END LC_CTYPE
|
Symbolic Name |
Other Case |
Character Classes |
|---|---|---|
|
<NUL> |
|
cntrl |
|
<SOH> |
|
cntrl |
|
<STX> |
|
cntrl |
|
<ETX> |
|
cntrl |
|
<EOT> |
|
cntrl |
|
<ENQ> |
|
cntrl |
|
<ACK> |
|
cntrl |
|
<alert> |
|
cntrl |
|
<backspace> |
|
cntrl |
|
<tab> |
|
cntrl, space, blank |
|
<newline> |
|
cntrl, space |
|
<vertical-tab> |
|
cntrl, space |
|
<form-feed> |
|
cntrl, space |
|
<carriage-return> |
|
cntrl, space |
|
<SO> |
|
cntrl |
|
<SI> |
|
cntrl |
|
<DLE> |
|
cntrl |
|
<DC1> |
|
cntrl |
|
<DC2> |
|
cntrl |
|
<DC3> |
|
cntrl |
|
<DC4> |
|
cntrl |
|
<NAK> |
|
cntrl |
|
<SYN> |
|
cntrl |
|
<ETB> |
|
cntrl |
|
<CAN> |
|
cntrl |
|
<EM> |
|
cntrl |
|
<SUB> |
|
cntrl |
|
<ESC> |
|
cntrl |
|
<IS4> |
|
cntrl |
|
<IS3> |
|
cntrl |
|
<IS2> |
|
cntrl |
|
<IS1> |
|
cntrl |
|
<space> |
|
space, print, blank |
|
<exclamation-mark> |
|
punct, print, graph |
|
<quotation-mark> |
|
punct, print, graph |
|
<number-sign> |
|
punct, print, graph |
|
<dollar-sign> |
|
punct, print, graph |
|
<percent-sign> |
|
punct, print, graph |
|
<ampersand> |
|
punct, print, graph |
|
<apostrophe> |
|
punct, print, graph |
|
<left-par |