преобразование строки (string transformation)
Пролог (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.
Имя (Name)
strxfrm, strxfrm_l — string transformation
Синопсис (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);
Описание (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.
Возвращаемое значение (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.
Ошибки (Error)
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.
Примеры (Examples)
None.
Использование в приложениях (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.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
strcmp(3p), strcoll(3p)
The Base Definitions volume of POSIX.1‐2017, string.h(0p)
