# wctrans

## PROLOG



           This manual page is part of the POSIX Programmer's Manual.  The
           Linux implementation of this interface may differ (consult the
           corresponding Linux manual page for details of Linux behavior), or
           the interface may not be implemented on Linux.
    


## NAME



           wctrans, wctrans_l — define character mapping
    


## SYNOPSIS



           #include <wctype.h>
    
           wctrans_t wctrans(const char *_charclass_);
           wctrans_t wctrans_l(const char *_charclass_ , locale_t _locale_);
    


## DESCRIPTION



           For _wctrans_(): The functionality described on this reference page
           is aligned with the ISO C standard. Any conflict between the
           requirements described here and the ISO C standard is
           unintentional. This volume of POSIX.1‐2017 defers to the ISO C
           standard.
    
           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**.
    
           These functions shall return 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 shall determine values of
           **wctrans_t** according to the rules of the coded character set
           defined by character mapping information in the current locale or
           in the locale represented by _locale_ , respectively (category
           _LC_CTYPE_).
    
           The values returned by _wctrans_() shall be valid until a call to
           _setlocale_() that modifies the category _LC_CTYPE_.
    
           The values returned by _wctrans_l_() shall be valid only in calls to
           _towctrans_l_() with a locale represented by _locale_ with the same
           _LC_CTYPE_ category value.
    
           The behavior is undefined if the _locale_ argument to _wctrans_l_() is
           the special locale object LC_GLOBAL_LOCALE or is not a valid
           locale object handle.
    


## RETURN VALUE



           The _wctrans_() and _wctrans_l_() functions 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,
           they shall return a non-zero object of type **wctrans_t** that can be
           used in calls to _towctrans_() and _towctrans_l_().
    


## ERRORS



           These functions may fail if:
    
           **EINVAL** The character mapping name pointed to by _charclass_ is not
                  valid in the current locale.
    
           _The following sections are informative._
    


## EXAMPLES



           None.
    


## APPLICATION USAGE



           None.
    


## RATIONALE



           None.
    


## FUTURE DIRECTIONS



           None.
    


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