Define character mapping.
Standard library (libc.a)
#include <wctype.h>wctrans_t wctrans (const char * charclass);
wctrans_t wctrans_l (const char * charclass, locale_t Locale);The wctrans and wctrans_l functions are defined for valid character mapping names identified in the current locale. The charclass is a string identifying a generic character mapping name for which codeset-specific information is required. The following character mapping names are defined in all locales "tolower" and "toupper".
The function returns a value of type wctrans_t, which can be used as the second argument to subsequent calls of towctrans and towctrans_l. The wctrans and wctrans_l functions determines values of wctrans_t according to the rules of the coded character set defined by character mapping information in the program's locale (category LC_CTYPE) or in the locale represented by Locale. The values returned by wctrans are valid until a call to setlocale that modifies the category LC_CTYPE.
The values returned by wctrans_l() function is valid only in calls to wctrans_l() function with a locale represented by Locale with the same LC_CTYPE category value.
The wctrans and wctrans_l functions return 0 if the given character mapping name is not valid for the current locale (category LC_CTYPE), otherwise it returns a non-zero object of type wctrans_t that can be used in calls to towctrans and towctrans_l.
The wctrans, and wctrans_l function may fail if:
| Item | Description |
|---|---|
| EINVAL | The character mapping name pointed to by charclass is not valid in the current locale. |