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mbstowcs(3)
NAME
  mbstowcs, mbsrtowcs - Converts a multibyte character string to a wide-
  character string

LIBRARY
  Standard C Library (libc.so, libc.a)

SYNOPSIS
  #include <stdlib.h>

  size_t mbstowcs(
	  wchar_t *pwcs,
	  const char *s,
	  size_t n);

  #include <wchar.h>

  size_t mbsrtowcs(
	  wchar_t *pwcs,
	  const char **s,
	  size_t n,
	  mbstate_t *ps );

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

  mbstowcs():  ISO C, XPG4

  mbsrtowcs():	ISO C

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

PARAMETERS
  *pwcs
      Points to the array where the result of the conversion is stored.

  *s or **s
      Points or indirectly points to the multibyte-character string to be
      converted.

  n   Specifies the number of wide characters in the destination array.

  *ps Points to an mbstate_t structure containing the conversion state of the
      data in s.


DESCRIPTION
  The mbstowcs() function converts a multibyte-character string into a wide-
  character string, which is stored at a specified location.  The function
  does not examine or convert any characters that follow a null byte, which
  is converted and stored as a wide-character code with value zero.  The
  function does not store more than n wide characters in pwcs.	When
  operating on overlapping strings, the behavior of this function is
  undefined.

  Behavior of the mbstowcs() function is affected by the LC_CTYPE category of
  the current locale.  In locales that use shift-state encoding, the array
  pointed to by the s parameter begins in the initial shift state.

  The mbsrtowcs() function is a restartable version of mbstowcs().
  Restartable conversion functions obtain and store the conversion state in
  an mbstate_t structure that can be read and changed by subsequent calls to
  the same or other restartable conversion functions.

RESTRICTIONS
  The mbsrtowcs() and other restartable versions of conversion functions are
  functional only when used with locales that support shift-state encoding.
  Currently, the DIGITAL UNIX product does not provide any locales that
  support shift-state encoding, so the mbstowcs() and mbsrtowcs() functions
  do not differ in terms of run-time behavior.

RETURN VALUES
  When the mbstowcs() and mbsrtowcs() functions encounter an invalid
  multibyte character during conversion, they return a value of -1 cast to
  size_t and set errno to indicate the error.  Otherwise, these functions
  return the number of wide characters stored in the output array, not
  including a terminating null wide character. (When the return value is n,
  the output array is not null-terminated.)

ERRORS
  If the following condition occurs, the mbstowcs() and mbsrtowcs() functions
  set errno to the corresponding value:

  [EILSEQ]
	 The s parameter contains an invalid multibyte character.

RELATED INFORMATION
  Functions: btowc(3), mblen(3), mbsinit(3), mbtowc(3), wcstombs(3),
  wcslen(3), wctob(3), wctomb(3)