STRXFRM
Section: POSIX Programmer's Manual (3P)
Updated: 2017
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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
strxfrm,
strxfrm_l
--- string transformation
SYNOPSIS
#include <string.h>
size_t strxfrm(char *restrict s1, const char *restrict s2, size_t n);
size_t strxfrm_l(char *restrict s1, const char *restrict s2,
size_t n, locale_t locale);
DESCRIPTION
For
strxfrm():
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
strxfrm()
and
strxfrm_l()
functions shall transform the string pointed to by
s2
and place the resulting string into the array pointed to by
s1.
The transformation is such that if
strcmp()
is applied to two transformed strings, it shall return a value greater
than, equal to, or less than 0, corresponding to the result of
strcoll()
or
strcoll_l(),
respectively, applied to the same two original strings
with the same locale.
No more than
n
bytes are placed into the resulting array pointed to by
s1,
including the terminating NUL character. If
n
is 0,
s1
is permitted to be a null pointer. If copying takes place between
objects that overlap, the behavior is undefined.
The
strxfrm()
and
strxfrm_l()
functions shall 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
strxfrm()
or
strxfrm_l(),
then check
errno.
The behavior is undefined if the
locale
argument to
strxfrm_l()
is the special locale object LC_GLOBAL_LOCALE or is not a valid locale
object handle.
RETURN VALUE
Upon successful completion,
strxfrm()
and
strxfrm_l()
shall return the length of the transformed string (not including the
terminating NUL character). If the value returned is
n
or more, the contents of the array pointed to by
s1
are unspecified.
On error,
strxfrm()
and
strxfrm_l()
may set
errno
but no return value is reserved to indicate an error.
ERRORS
These functions may fail if:
- EINVAL
-
The string pointed to by the
s2
argument contains characters outside the domain of the collating
sequence.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
The transformation function is such that two transformed strings can be
ordered by
strcmp()
as appropriate to collating sequence information in the
current locale (category
LC_COLLATE).
The fact that when
n
is 0
s1
is permitted to be a null pointer is useful to determine the size of
the
s1
array prior to making the transformation.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
strcmp(),
strcoll()
The Base Definitions volume of POSIX.1-2017,
<string.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 .