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wcsxfrm(3)
NAME
  wcsxfrm - Transform wide-character strings for collation in the current
  locale

SYNOPSIS
  #include <wchar.h>

  size_t wcsxfrm(
	  wchar_t *ws1,
	  const wchar_t *ws2,
	  size_t n );

LIBRARY
  Standard C Library (libc)

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  wcsxfrm(): XSH5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  ws1 Contains a pointer to the destination wide-character string.

  ws2
      Contains a pointer to the source wide-character string.

  n   Specifies the maximum number of wide-character codes to place into the
      array specified by ws1.

DESCRIPTION
  The wcsxfrm() function is used to transform the wide-character string
  specified by the ws2 parameter into a string of wide-character codes based
  on the collation values of the wide characters in the current setting of
  the LC_COLLATE locale category. No more than n wide characters (including
  the terminating null wide character) are copied into the array specified by
  the ws1 parameter.  When two transformed wide-character strings are
  obtained and the transformed strings are compared using wcscmp(), the
  result is the same as that obtained by a direct call to wcscoll() on the
  two original wide-character strings.

  The application can call wcsxfrm() with ws1 as a null pointer to determine
  the number of wide characters to allocate for the ws1 parameter. For
  example, the following expression calculates the size of ws1:

       1 + wcsxfrm(NULL, ws2, 0)

  As shown in this example, the n parameter must be 0 (zero) when ws1 is a
  null pointer.

  When operating on overlapping strings, the behavior of the wcsxfrm()
  function is unreliable.

NOTES
  If an application does multiple comparisons based on the current locale's
  collation values and uses the same set of text strings, the wcsxfrm()
  transformation function in conjunction with the wcscmp() function may be
  more efficient than the wcscoll() collation function. This is because the
  string is transformed based on the locale tables only once. However, the
  transformation function must convert all characters in the string for each
  level of a multilevel collation. In comparison, the collation function
  stops comparing characters at the first inequality. These tradeoffs make
  the most efficient method for a specific application dependent on the
  number of repeated comparisons of strings within the set, the number of
  collation levels for the current locale, and the values of the strings
  within the set.

RETURN VALUES
  If the ws1 parameter is a wide-character null pointer, the wcsxfrm()
  function returns the number of wide-character elements (not including the
  terminating null wide character) required to store the transformed wide-
  character string. If the count specified by the n parameter is sufficient
  to hold the transformed string in the ws1 parameter (including the
  terminating null wide character) the return value is set to the actual
  number of wide-character elements placed in the ws1 parameter, not
  including the terminating null wide character. If the return value is equal
  to or greater than the value specified by the n parameter, the contents of
  the array pointed to by the ws1 parameter are indeterminate.

  On error, the wcsxfrm() function returns (size_t)-1 and sets errno to
  indicate the error.

ERRORS
  If any the following conditions occur, the wcsxfrm() function sets errno to
  the corresponding value:

  [EINVAL]
      The ws2 parameter contains wide-character codes outside the domain of
      the collating sequence defined by the current locale.

  [ENOMEM]
      [Tru64 UNIX]  There was insufficient memory available to allocate
      temporary storage for this operation.

SEE ALSO
  Functions: setlocale(3), string(3), wcscmp(3), wcscoll(3)

  Standards: standards(5)

Index for Section 3

Alphabetical listing for W

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