iswalphaLA

iswalphaLA is a locale-aware variant of the wide-character classification function used in some programming libraries. It is designed to determine whether a given wide character is alphabetic when operating under a specific locale designated as LA. The function extends the basic concept of alphabetic testing beyond a global or default locale by tying the classification to the LA locale’s data set.

Definition and purpose

iswalphaLA accepts a wide character input and returns a nonzero value if the character is considered alphabetic according to the rules defined for the LA locale; it returns zero otherwise. The LA locale provides its own set of alphabetic code points, which may include standard Latin letters as well as extended characters used in languages that employ Latin scripts. The approach aims to deliver predictable behavior for internationalized applications that rely on locale-specific definitions of what constitutes an alphabetic character.

Relation to standard functions

iswalphaLA is related to the standard wide-character function iswalpha, but instead of using the global or current locale, it consults the data associated with the LA locale. This makes iswalphaLA useful in environments where multiple locales are in use within the same application, enabling explicit and reproducible alphabetic classification for the LA context.

Implementation considerations

Implementations of iswalphaLA typically require a locale data table for LA, potentially sourced from existing Unicode properties or a dedicated locale database. Performance considerations include the cost of locale initialization and data lookups, as well as thread-safety when the LA data is shared across threads. Compatibility with LC_CTYPE and similar locale mechanisms may influence how LA data is loaded and referenced.

See also

iswalpha, locale, internationalization, Unicode character properties.