Section: POSIX Programmer's Manual (3P)
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.
--- string transformation
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);
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.
functions shall transform the string pointed to by
and place the resulting string into the array pointed to by
The transformation is such that if
is applied to two transformed strings, it shall return a value greater
than, equal to, or less than 0, corresponding to the result of
respectively, applied to the same two original strings
with the same locale.
No more than
bytes are placed into the resulting array pointed to by
including the terminating NUL character. If
is permitted to be a null pointer. If copying takes place between
objects that overlap, the behavior is undefined.
functions shall not change the setting of
Since no return value is reserved to indicate an error, an
application wishing to check for error situations should set
to 0, then call
The behavior is undefined if the
is the special locale object LC_GLOBAL_LOCALE or is not a valid locale
Upon successful completion,
shall return the length of the transformed string (not including the
terminating NUL character). If the value returned is
or more, the contents of the array pointed to by
but no return value is reserved to indicate an error.
These functions may fail if:
The string pointed to by the
argument contains characters outside the domain of the collating
The following sections are informative.
The transformation function is such that two transformed strings can be
as appropriate to collating sequence information in the
current locale (category
The fact that when
is permitted to be a null pointer is useful to determine the size of
array prior to making the transformation.
The Base Definitions volume of POSIX.1-2017,
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
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