PROLOG

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

NAME

       strcoll, strcoll_l — string comparison using collating information

SYNOPSIS

       #include <string.h>

       int strcoll(const char *s1, const char *s2);
       int strcoll_l(const char *s1, const char *s2,
           locale_t locale);

DESCRIPTION

       For strcoll(): The functionality described on this reference page is aligned with the ISO C standard. Any
       conflict  between the requirements described here and the ISO C standard is unintentional. This volume of
       POSIX.1‐2017 defers to the ISO C standard.

       The strcoll() and strcoll_l() functions shall compare the string pointed to by s1 to the  string  pointed
       to  by  s2,  both  interpreted as appropriate to the LC_COLLATE category of the current locale, or of the
       locale represented by locale, respectively.

       The strcoll() and strcoll_l() functions 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 strcoll(), or strcoll_l() then check errno.

       The  behavior  is  undefined  if  the  locale  argument  to  strcoll_l()  is  the  special  locale object
       LC_GLOBAL_LOCALE or is not a valid locale object handle.

RETURN VALUE

       Upon successful completion, strcoll() shall return an integer greater than, equal to,  or  less  than  0,
       according  to  whether  the  string  pointed  to by s1 is greater than, equal to, or less than the string
       pointed to by s2 when both are interpreted as appropriate to the current locale.  On error, strcoll() may
       set errno, but no return value is reserved to indicate an error.

       Upon successful completion, strcoll_l() shall return an integer greater than, equal to, or less  than  0,
       according  to  whether  the  string  pointed  to by s1 is greater than, equal to, or less than the string
       pointed to by s2 when both are interpreted as appropriate to the locale represented by locale.  On error,
       strcoll_l() may set errno, but no return value is reserved to indicate an error.

ERRORS

       These functions may fail if:

       EINVAL The s1 or s2 arguments contain characters outside the domain of the collating sequence.

       The following sections are informative.

EXAMPLES

   Comparing Nodes
       The following example uses an application-defined function, node_compare(), to compare two nodes based on
       an alphabetical ordering of the string field.

           #include <string.h>
           ...
           struct node { /* These are stored in the table. */
               char *string;
               int length;
           };
           ...
           int node_compare(const void *node1, const void *node2)
           {
               return strcoll(((const struct node *)node1)->string,
                   ((const struct node *)node2)->string);
           }
           ...

APPLICATION USAGE

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

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       alphasort(), strcmp(), strxfrm()

       The Base Definitions volume of POSIX.1‐2017, <string.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 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 .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                       STRCOLL(3POSIX)