Tribblix: manual page: wcsxfrm.3c

WCSXFRM(3C) Standard C Library Functions WCSXFRM(3C)

NAME

wcsxfrm, wsxfrm - wide character string transformation

SYNOPSIS

#include <wchar.h>

size_t wcsxfrm(wchar_t *ws1, const wchar_t *ws2, size_t n);

size_t wsxfrm(wchar_t *ws1, const wchar_t *ws2, size_t n);

DESCRIPTION

The wcsxfrm() and wcsxfrm() functions transform the wide character
string pointed to by ws2 and place the resulting wide character
string into the array pointed to by ws1. The transformation is such
that if either the wcscmp(3C) or wscmp(3C) functions are applied to
two transformed wide strings, they return a value greater than, equal
to, or less than 0, corresponding to the result of the wcscoll(3C)
or wscoll(3C) function applied to the same two original wide
character strings. No more than n wide-character codes are placed
into the resulting array pointed to by ws1, including the terminating
null wide-character code. If n is 0, ws1 is permitted to be a null
pointer. If copying takes place between objects that overlap, the
behavior is undefined.

The wcsxfrm() and wsxfrm() functions do not change the setting of
errno if successful.

Since no return value is reserved to indicate an error, an
application wishing to check for error situations should set errno to
0, then call wcsxfrm() or wsxfrm(), then check errno.

RETURN VALUES

The wcsxfrm() and wsxfrm() functions return the length of the
transformed wide character string (not including the terminating null
wide-character code). If the value returned is n or more, the
contents of the array pointed to by ws1 are indeterminate.

On error, wcsxfrm() and wsxfrm() may set errno but no return value is
reserved to indicate an error.

ERRORS

The wcsxfrm() and wsxfrm() functions may fail if:

EINVAL
The wide character string pointed to by ws2 contains wide-
character codes outside the domain of the collating
sequence.

USAGE

The transformation function is such that two transformed wide
character strings can be ordered by the wcscmp() or wscmp() functions
as appropriate to collating sequence information in the program's
locale (category LC_COLLATE).

The fact that when n is 0, ws1 is permitted to be a null pointer, is
useful to determine the size of the ws1 array prior to making the
transformation.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:

+--------------------+-------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------------+
|CSI | Enabled |
+--------------------+-------------------------+
|Interface Stability | wcsxfrm() is Standard |
+--------------------+-------------------------+
|MT-Level | MT-Safe with exceptions |
+--------------------+-------------------------+

The wcsxfrm() and wsxfrm() functions can be used safely in
multithreaded applications as long as setlocale(3C) is not being
called to change the locale.