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
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.
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.
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
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