.\" Copyright (c) 2002 Tim J. Robbins
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.\" $FreeBSD$
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.Dd October 3, 2002
.Dt WCTRANS 3
.Os
.Sh NAME
.Nm towctrans , wctrans
.Nd "wide character mapping functions"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In wctype.h
.Ft wint_t
.Fn towctrans "wint_t wc" "wctrans_t desc"
.Ft wctrans_t
.Fn wctrans "const char *charclass"
.Sh DESCRIPTION
The
.Fn wctrans
function returns a value of type
.Vt wctrans_t
which represents the requested wide character mapping operation and
may be used as the second argument for calls to
.Fn towctrans .
.Pp
The following character mapping names are recognised:
.Bl -column -offset indent ".Li tolower" ".Li toupper"
.It Li "tolower	toupper"
.El
.Pp
The
.Fn towctrans
function transliterates the wide character
.Fa wc
according to the mapping described by
.Fa desc .
.Sh RETURN VALUES
The
.Fn towctrans
function returns the transliterated character if successful, otherwise
it returns the character unchanged and sets
.Va errno .
.Pp
The
.Fn wctrans
function returns non-zero if successful, otherwise it returns zero
and sets
.Va errno .
.Sh EXAMPLES
Reimplement
.Fn towupper
in terms of
.Fn towctrans
and
.Fn wctrans :
.Bd -literal -offset indent
wint_t
mytowupper(wint_t wc)
{
	return (towctrans(wc, wctrans("toupper")));
}
.Ed
.Sh ERRORS
The
.Fn towctrans
function will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The supplied
.Fa desc
argument is invalid.
.El
.Pp
The
.Fn wctrans
function will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The requested mapping name is invalid.
.El
.Sh SEE ALSO
.Xr tolower 3 ,
.Xr toupper 3 ,
.Xr wctype 3
.Sh STANDARDS
The
.Fn towctrans
and
.Fn wctrans
functions conform to
.St -p1003.1-2001 .
.Sh HISTORY
The
.Fn towctrans
and
.Fn wctrans
functions first appeared in
.Fx 5.0 .