strcoll(3p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

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

PROLOG         top

       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         top

       strcoll, strcoll_l — string comparison using collating
       information

SYNOPSIS         top

       #include <string.h>

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

DESCRIPTION         top

       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         top

       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         top

       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         top

   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         top

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

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       alphasort(3p), strcmp(3p), strxfrm(3p)

       The Base Definitions volume of POSIX.1‐2017, string.h(0p)

COPYRIGHT         top

       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(3P)

Pages that refer to this page: string.h(0p)alphasort(3p)localeconv(3p)setlocale(3p)strxfrm(3p)