1STRCOLL(3P)                POSIX Programmer's Manual               STRCOLL(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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11

NAME

13       strcoll, strcoll_l — string comparison using collating information
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SYNOPSIS

16       #include <string.h>
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18       int strcoll(const char *s1, const char *s2);
19       int strcoll_l(const char *s1, const char *s2,
20           locale_t locale);
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DESCRIPTION

23       For strcoll(): The functionality described on this  reference  page  is
24       aligned  with the ISO C standard. Any conflict between the requirements
25       described here and the ISO C standard is unintentional. This volume  of
26       POSIX.1‐2008 defers to the ISO C standard.
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28       The  strcoll()  and  strcoll_l()  functions  shall  compare  the string
29       pointed to by s1 to the string pointed to by s2,  both  interpreted  as
30       appropriate to the LC_COLLATE category of the current locale, or of the
31       locale represented by locale, respectively.
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33       The strcoll() and strcoll_l() functions shall not change the setting of
34       errno if successful.
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36       Since  no return value is reserved to indicate an error, an application
37       wishing to check for error situations should set errno to 0, then  call
38       strcoll(), or strcoll_l() then check errno.
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40       The  behavior is undefined if the locale argument to strcoll_l() is the
41       special locale object LC_GLOBAL_LOCALE or is not a valid locale  object
42       handle.
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RETURN VALUE

45       Upon  successful  completion, strcoll() shall return an integer greater
46       than, equal to, or less than 0, according to whether the string pointed
47       to  by s1 is greater than, equal to, or less than the string pointed to
48       by s2 when both are interpreted as appropriate to the  current  locale.
49       On  error,  strcoll() may set errno, but no return value is reserved to
50       indicate an error.
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52       Upon successful completion, strcoll_l() shall return an integer greater
53       than, equal to, or less than 0, according to whether the string pointed
54       to by s1 is greater than, equal to, or less than the string pointed  to
55       by  s2  when  both  are interpreted as appropriate to the locale repre‐
56       sented by locale.  On error, strcoll_l() may set errno, but  no  return
57       value is reserved to indicate an error.
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ERRORS

60       These functions may fail if:
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62       EINVAL The  s1 or s2 arguments contain characters outside the domain of
63              the collating sequence.
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65       The following sections are informative.
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EXAMPLES

68   Comparing Nodes
69       The following example uses an application-defined  function,  node_com‐
70       pare(),  to  compare two nodes based on an alphabetical ordering of the
71       string field.
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73           #include <string.h>
74           ...
75           struct node { /* These are stored in the table. */
76               char *string;
77               int length;
78           };
79           ...
80           int node_compare(const void *node1, const void *node2)
81           {
82               return strcoll(((const struct node *)node1)->string,
83                   ((const struct node *)node2)->string);
84           }
85           ...
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APPLICATION USAGE

88       The strxfrm() and strcmp() functions should be used for  sorting  large
89       lists.
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RATIONALE

92       None.
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FUTURE DIRECTIONS

95       None.
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SEE ALSO

98       alphasort(), strcmp(), strxfrm()
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100       The Base Definitions volume of POSIX.1‐2008, <string.h>
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103       Portions  of  this text are reprinted and reproduced in electronic form
104       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
105       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
106       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
107       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
108       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
109       event of any discrepancy between this version and the original IEEE and
110       The Open Group Standard, the original IEEE and The Open Group  Standard
111       is  the  referee document. The original Standard can be obtained online
112       at http://www.unix.org/online.html .
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114       Any typographical or formatting errors that appear  in  this  page  are
115       most likely to have been introduced during the conversion of the source
116       files to man page format. To report such errors,  see  https://www.ker
117       nel.org/doc/man-pages/reporting_bugs.html .
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121IEEE/The Open Group                  2013                          STRCOLL(3P)
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