MBSTOWCS(3P) POSIX Programmer's Manual MBSTOWCS(3P)
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.
mbstowcs - convert a character string to a wide-character string
size_t mbstowcs(wchar_t *restrict pwcs, const char *restrict s,
The mbstowcs() function shall convert a sequence of characters that begins in the initial
shift state from the array pointed to by s into a sequence of corresponding wide-character
codes and shall store not more than n wide-character codes into the array pointed to by
pwcs. No characters that follow a null byte (which is converted into a wide-character code
with value 0) shall be examined or converted. Each character shall be converted as if by a
call to mbtowc(), except that the shift state of mbtowc() is not affected.
No more than n elements shall be modified in the array pointed to by pwcs. If copying
takes place between objects that overlap, the behavior is undefined.
The behavior of this function shall be affected by the LC_CTYPE category of the current
locale. If pwcs is a null pointer, mbstowcs() shall return the length required to convert
the entire array regardless of the value of n, but no values are stored.
If an invalid character is encountered, mbstowcs() shall return (size_t)-1 and may set
errno to indicate the error.
Otherwise, mbstowcs() shall return the number of the array elements modified (or required
if pwcs is null), not including a terminating 0 code, if any. The array shall not be
zero-terminated if the value returned is n.
The mbstowcs() function may fail if:
EILSEQ Invalid byte sequence is detected.
The following sections are informative.
mblen(), mbtowc(), wctomb(), wcstombs(), the Base Definitions volume of
IEEE Std 1003.1-2001, <stdlib.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 MBSTOWCS(3P)