NAME
strxfrm - string transformation
SYNOPSIS
#include <string.h>
size_t strxfrm(char *restrict s1, const char *restrict s2, size_t n);
DESCRIPTION
The strxfrm() function 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() applied to the same two
original strings. No more than n bytes are placed into the resulting
array pointed to by s1, including the terminating null byte. 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() function 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(), then check errno.
RETURN VALUE
Upon successful completion, strxfrm() shall return the length of the
transformed string (not including the terminating null byte). If the
value returned is n or more, the contents of the array pointed to by s1
are unspecified.
On error, strxfrm() may set errno but no return value is reserved to
indicate an error.
ERRORS
The strxfrm() function 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 program’s 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
IEEE Std 1003.1-2001, <string.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 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 .