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

       towctrans, towctrans_l — wide-character transliteration

SYNOPSIS

       #include <wctype.h>

       wint_t towctrans(wint_t wc, wctrans_t desc);
       wint_t towctrans_l(wint_t wc, wctrans_t desc,
           locale_t locale);

DESCRIPTION

       For  towctrans():  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 towctrans() and towctrans_l() functions shall transliterate the wide-character code wc
       using the mapping described by desc.

       The current setting of the LC_CTYPE category in  the  current  locale  or  in  the  locale
       represented by locale, respectively, should be the same as during the call to wctrans() or
       wctrans_l() that returned the value desc.

       If the value of desc is invalid (that is, not obtained by a call to wctrans() or  desc  is
       invalidated  by a subsequent call to setlocale() that has affected category LC_CTYPE), the
       result is unspecified.

       If the value of desc is invalid (that is, not obtained by a call to wctrans_l()  with  the
       same locale object locale) the result is unspecified.

       An  application wishing to check for error situations should set errno to 0 before calling
       towctrans() or towctrans_l().

       If errno is non-zero on return, an error has occurred.

       The behavior is undefined if the locale argument to towctrans_l() is  the  special  locale
       object LC_GLOBAL_LOCALE or is not a valid locale object handle.

RETURN VALUE

       If  successful,  the towctrans() and towctrans_l() functions shall return the mapped value
       of wc using the mapping described by desc.  Otherwise, they shall return wc unchanged.

ERRORS

       These functions may fail if:

       EINVAL desc contains an invalid transliteration descriptor.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The strings "tolower" and "toupper" are reserved for the standard mapping  names.  In  the
       table below, the functions in the left column are equivalent to the functions in the right
       column.

           towlower(wc)            towctrans(wc, wctrans("tolower"))
           towlower_l(wc, locale)  towctrans_l(wc, wctrans("tolower"), locale)
           towupper(wc)            towctrans(wc, wctrans("toupper"))
           towupper_l(wc, locale)  towctrans_l(wc, wctrans("toupper"), locale)

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       towlower(), towupper(), wctrans()

       The Base Definitions volume of POSIX.1‐2017, <wctype.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1-2017,  Standard  for  Information Technology -- Portable Operating System Interface
       (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C)  2018  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 .

       Any typographical or formatting errors that appear in this page are most  likely  to  have
       been  introduced  during  the conversion of the source files to man page format. To report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .