1STRXFRM(P)                 POSIX Programmer's Manual                STRXFRM(P)
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NAME

6       strxfrm - string transformation
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SYNOPSIS

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

15       The  strxfrm() function shall transform the string pointed to by s2 and
16       place the resulting string into the array pointed to by s1. The  trans‐
17       formation  is  such  that  if  strcmp()  is  applied to two transformed
18       strings, it shall return a value greater than, equal to, or  less  than
19       0,  corresponding  to  the  result of strcoll() applied to the same two
20       original strings. No more than n bytes are placed  into  the  resulting
21       array pointed to by s1, including the terminating null byte. If n is 0,
22       s1 is permitted to be a null pointer. If copying  takes  place  between
23       objects that overlap, the behavior is undefined.
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25       The  strxfrm()  function  shall not change the setting of errno if suc‐
26       cessful.
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28       Since no return value is reserved to indicate an error, an  application
29       wishing  to check for error situations should set errno to 0, then call
30       strxfrm(), then check errno.
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RETURN VALUE

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

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

51       None.
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APPLICATION USAGE

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

63       None.
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FUTURE DIRECTIONS

66       None.
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SEE ALSO

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