1STRXFRM(3P)                POSIX Programmer's Manual               STRXFRM(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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NAME

12       strxfrm - string transformation
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SYNOPSIS

15       #include <string.h>
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17       size_t strxfrm(char *restrict s1, const char *restrict s2, size_t n);
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DESCRIPTION

21       The strxfrm() function shall transform the string pointed to by s2  and
22       place  the resulting string into the array pointed to by s1. The trans‐
23       formation is such that  if  strcmp()  is  applied  to  two  transformed
24       strings,  it  shall return a value greater than, equal to, or less than
25       0, corresponding to the result of strcoll() applied  to  the  same  two
26       original  strings.  No  more than n bytes are placed into the resulting
27       array pointed to by s1, including the terminating null byte. If n is 0,
28       s1  is  permitted  to be a null pointer. If copying takes place between
29       objects that overlap, the behavior is undefined.
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31       The strxfrm() function shall not change the setting of  errno  if  suc‐
32       cessful.
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34       Since  no return value is reserved to indicate an error, an application
35       wishing to check for error situations should set errno to 0, then  call
36       strxfrm(), then check errno.
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RETURN VALUE

39       Upon  successful  completion,  strxfrm() shall return the length of the
40       transformed string (not including the terminating null  byte).  If  the
41       value returned is n or more, the contents of the array pointed to by s1
42       are unspecified.
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44       On error, strxfrm() may set errno but no return value  is  reserved  to
45       indicate an error.
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ERRORS

48       The strxfrm() function may fail if:
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50       EINVAL The  string  pointed  to  by the s2 argument contains characters
51              outside the domain of the collating sequence.
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54       The following sections are informative.
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EXAMPLES

57       None.
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APPLICATION USAGE

60       The transformation function is such that two transformed strings can be
61       ordered by strcmp() as appropriate to collating sequence information in
62       the program's locale (category LC_COLLATE ).
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64       The fact that when n is 0 s1 is permitted to be a null pointer is  use‐
65       ful to determine the size of the s1 array prior to making the transfor‐
66       mation.
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RATIONALE

69       None.
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FUTURE DIRECTIONS

72       None.
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SEE ALSO

75       strcmp(),    strcoll(),    the    Base    Definitions     volume     of
76       IEEE Std 1003.1-2001, <string.h>
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79       Portions  of  this text are reprinted and reproduced in electronic form
80       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
81       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
82       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
83       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
84       event of any discrepancy between this version and the original IEEE and
85       The  Open Group Standard, the original IEEE and The Open Group Standard
86       is the referee document. The original Standard can be  obtained  online
87       at http://www.opengroup.org/unix/online.html .
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91IEEE/The Open Group                  2003                          STRXFRM(3P)
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