strxfrm(3p) — Linux manual page

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

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

       strxfrm, strxfrm_l — string transformation

SYNOPSIS

       #include <string.h>

       size_t strxfrm(char *restrict s1, const char *restrict s2, size_t n);
       size_t strxfrm_l(char *restrict s1, const char *restrict s2,
           size_t n, locale_t locale);

DESCRIPTION

       For strxfrm(): 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 strxfrm() and strxfrm_l() functions shall transform the
       string pointed to by s2 and place the resulting string into the
       array pointed to by s1.  The transformation is such that if
       strcmp() is applied to two transformed strings, it shall return a
       value greater than, equal to, or less than 0, corresponding to
       the result of strcoll() or strcoll_l(), respectively, applied to
       the same two original strings with the same locale.  No more than
       n bytes are placed into the resulting array pointed to by s1,
       including the terminating NUL character. If n is 0, s1 is
       permitted to be a null pointer. If copying takes place between
       objects that overlap, the behavior is undefined.

       The strxfrm() and strxfrm_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 strxfrm() or strxfrm_l(), then check errno.

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

RETURN VALUE

       Upon successful completion, strxfrm() and strxfrm_l() shall
       return the length of the transformed string (not including the
       terminating NUL character). If the value returned is n or more,
       the contents of the array pointed to by s1 are unspecified.

       On error, strxfrm() and strxfrm_l() may set errno but no return
       value is reserved to indicate an error.

ERRORS

       These functions may fail if:

       EINVAL The string pointed to by the s2 argument contains
              characters outside the domain of the collating sequence.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The transformation function is such that two transformed strings
       can be ordered by strcmp() as appropriate to collating sequence
       information in the current locale (category LC_COLLATE).

       The fact that when n is 0 s1 is permitted to be a null pointer is
       useful to determine the size of the s1 array prior to making the
       transformation.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       strcmp(3p), strcoll(3p)

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

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                       STRXFRM(3P)

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

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