8.2 Internationalization Variables
This section describes environment variables that are relevant to the operation of internationalized interfaces described in IEEE Std 1003.1-2001.
Users may use the following environment variables to announce specific localization requirements to applications. Applications can retrieve this information using the setlocale() function to initialize the correct behavior of the internationalized interfaces. The descriptions of the internationalization environment variables describe the resulting behavior only when the application locale is initialized in this way. The use of the internationalization variables by utilities described in the Shell and Utilities volume of IEEE Std 1003.1-2001 is described in the ENVIRONMENT VARIABLES section for those utilities in addition to the global effects described in this section.
LANG
This variable shall determine the locale category for native language, local customs, and coded character set in the absence of the LC_ALL and other LC_* ( LC_COLLATE , LC_CTYPE , LC_MESSAGES , LC_MONETARY , LC_NUMERIC , LC_TIME ) environment variables. This can be used by applications to determine the language to use for error messages and instructions, collating sequences, date formats, and so on.
LC_ALL
This variable shall determine the values for all locale categories. The value of the LC_ALL environment variable has precedence over any of the other environment variables starting with LC_ ( LC_COLLATE , LC_CTYPE , LC_MESSAGES , LC_MONETARY , LC_NUMERIC , LC_TIME ) and the LANG environment variable.
LC_COLLATE
This variable shall determine the locale category for character collation. It determines collation information for regular expressions and sorting, including equivalence classes and multi-character collating elements, in various utilities and the strcoll() and strxfrm() functions. Additional semantics of this variable, if any, are implementation-defined.
LC_CTYPE
This variable shall determine the locale category for character handling functions, such as tolower(), toupper(), and isalpha(). This environment variable determines the interpretation of sequences of bytes of text data as characters (for example, single as opposed to multi-byte characters), the classification of characters (for example, alpha, digit, graph), and the behavior of character classes. Additional semantics of this variable, if any, are implementation-defined.
LC_MESSAGES
This variable shall determine the locale category for processing affirmative and negative responses and the language and cultural conventions in which messages should be written. [XSI] It also affects the behavior of the catopen() function in determining the message catalog. Additional semantics of this variable, if any, are implementation-defined. The language and cultural conventions of diagnostic and informative messages whose format is unspecified by IEEE Std 1003.1-2001 should be affected by the setting of LC_MESSAGES .
LC_MONETARY
This variable shall determine the locale category for monetary-related numeric formatting information. Additional semantics of this variable, if any, are implementation-defined.
LC_NUMERIC
This variable shall determine the locale category for numeric formatting (for example, thousands separator and radix character) information in various utilities as well as the formatted I/O operations in printf() and scanf() and the string conversion functions in strtod(). Additional semantics of this variable, if any, are implementation-defined.
LC_TIME
This variable shall determine the locale category for date and time formatting information. It affects the behavior of the time functions in strftime(). Additional semantics of this variable, if any, are implementation-defined.
NLSPATH
[XSI] This variable shall contain a sequence of templates that the catopen() function uses when attempting to locate message catalogs. Each template consists of an optional prefix, one or more conversion specifications, a filename, and an optional suffix
