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.1‐2008 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.1‐2008, <string.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2013 Edition, Standard for Information Technology  --  Portable  Operating  System
       Interface  (POSIX),  The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc  and  The  Open  Group.   (This  is
       POSIX.1-2008  with  the  2013  Technical  Corrigendum  1  applied.)  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.unix.org/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 .