wctrans_t wctrans(const char *charclass);
The wctrans() function is 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 shall return a value of type wctrans_t, which can be used as the second argument to subsequent calls of towctrans(). The wctrans() function shall determine 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 ). The values returned by wctrans() shall be valid until a call to setlocale() that modifies the category LC_CTYPE .
The wctrans() function shall return 0 and may set errno to indicate the error if the given character mapping name is not valid for the current locale (category LC_CTYPE ); otherwise, it shall return a non-zero object of type wctrans_t that can be used in calls to towctrans().
The wctrans() function may fail if:
The character mapping name pointed to by charclass is not valid
in the current locale.
The following sections are informative.
COPYRIGHTPortions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .