STRXFRM(3P)                                         POSIX Programmer's Manual                                        STRXFRM(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

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, Copy-
       right (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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                   STRXFRM(3P)