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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
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NAME
wchar.h — wide-character handling
SYNOPSIS
#include <wchar.h>
DESCRIPTION
Some of the functionality described on this reference page extends the ISO C standard. Applications shall
define the appropriate feature test macro (see the System Interfaces volume of POSIX.1‐2017, Section 2.2,
The Compilation Environment) to enable the visibility of these symbols in this header.
The <wchar.h> header shall define the following types:
FILE As described in <stdio.h>.
locale_t As described in <locale.h>.
mbstate_t An object type other than an array type that can hold the conversion state information
necessary to convert between sequences of (possibly multi-byte) characters and wide
characters. If a codeset is being used such that an mbstate_t needs to preserve more than
two levels of reserved state, the results are unspecified.
size_t As described in <stddef.h>.
va_list As described in <stdarg.h>.
wchar_t As described in <stddef.h>.
wctype_t A scalar type of a data object that can hold values which represent locale-specific character
classification.
wint_t An integer type capable of storing any valid value of wchar_t or WEOF.
The tag tm shall be declared as naming an incomplete structure type, the contents of which are described
in the <time.h> header.
The implementation shall support one or more programming environments in which the width of wint_t is no
greater than the width of type long. The names of these programming environments can be obtained using
the confstr() function or the getconf utility.
The <wchar.h> header shall define the following macros:
WCHAR_MAX As described in <stdint.h>.
WCHAR_MIN As described in <stdint.h>.
WEOF Constant expression of type wint_t that is returned by several WP functions to indicate end-
of-file.
NULL As described in <stddef.h>.
Inclusion of the <wchar.h> header may make visible all symbols from the headers <ctype.h>, <string.h>,
<stdarg.h>, <stddef.h>, <stdio.h>, <stdlib.h>, and <time.h>.
The following shall be declared as functions and may also be defined as macros. Function prototypes shall
be provided for use with ISO C standard compilers. Arguments to functions in this list can point to
arrays containing wchar_t values that do not correspond to members of the character set of the current
locale. Such values shall be processed according to the specified semantics, unless otherwise stated.
wint_t btowc(int);
wint_t fgetwc(FILE *);
wchar_t *fgetws(wchar_t *restrict, int, FILE *restrict);
wint_t fputwc(wchar_t, FILE *);
int fputws(const wchar_t *restrict, FILE *restrict);
int fwide(FILE *, int);
int fwprintf(FILE *restrict, const wchar_t *restrict, ...);
int fwscanf(FILE *restrict, const wchar_t *restrict, ...);
wint_t getwc(FILE *);
wint_t getwchar(void);
int iswalnum(wint_t);
int iswalpha(wint_t);
int iswcntrl(wint_t);
int iswctype(wint_t, wctype_t);
int iswdigit(wint_t);
int iswgraph(wint_t);
int iswlower(wint_t);
int iswprint(wint_t);
int iswpunct(wint_t);
int iswspace(wint_t);
int iswupper(wint_t);
int iswxdigit(wint_t);
size_t mbrlen(const char *restrict, size_t, mbstate_t *restrict);
size_t mbrtowc(wchar_t *restrict, const char *restrict, size_t,
mbstate_t *restrict);
int mbsinit(const mbstate_t *);
size_t mbsnrtowcs(wchar_t *restrict, const char **restrict,
size_t, size_t, mbstate_t *restrict);
size_t mbsrtowcs(wchar_t *restrict, const char **restrict, size_t,
mbstate_t *restrict);
FILE *open_wmemstream(wchar_t **, size_t *);
wint_t putwc(wchar_t, FILE *);
wint_t putwchar(wchar_t);
int swprintf(wchar_t *restrict, size_t,
const wchar_t *restrict, ...);
int swscanf(const wchar_t *restrict,
const wchar_t *restrict, ...);
wint_t towlower(wint_t);
wint_t towupper(wint_t);
wint_t ungetwc(wint_t, FILE *);
int vfwprintf(FILE *restrict, const wchar_t *restrict, va_list);
int vfwscanf(FILE *restrict, const wchar_t *restrict, va_list);
int vswprintf(wchar_t *restrict, size_t,
const wchar_t *restrict, va_list);
int vswscanf(const wchar_t *restrict, const wchar_t *restrict,
va_list);
int vwprintf(const wchar_t *restrict, va_list);
int vwscanf(const wchar_t *restrict, va_list);
wchar_t *wcpcpy(wchar_t *restrict, const wchar_t *restrict);
wchar_t *wcpncpy(wchar_t *restrict, const wchar_t *restrict, size_t);
size_t wcrtomb(char *restrict, wchar_t, mbstate_t *restrict);
int wcscasecmp(const wchar_t *, const wchar_t *);
int wcscasecmp_l(const wchar_t *, const wchar_t *, locale_t);
wchar_t *wcscat(wchar_t *restrict, const wchar_t *restrict);
wchar_t *wcschr(const wchar_t *, wchar_t);
int wcscmp(const wchar_t *, const wchar_t *);
int wcscoll(const wchar_t *, const wchar_t *);
int wcscoll_l(const wchar_t *, const wchar_t *, locale_t);
wchar_t *wcscpy(wchar_t *restrict, const wchar_t *restrict);
size_t wcscspn(const wchar_t *, const wchar_t *);
wchar_t *wcsdup(const wchar_t *);
size_t wcsftime(wchar_t *restrict, size_t,
const wchar_t *restrict, const struct tm *restrict);
size_t wcslen(const wchar_t *);
int wcsncasecmp(const wchar_t *, const wchar_t *, size_t);
int wcsncasecmp_l(const wchar_t *, const wchar_t *, size_t,
locale_t);
wchar_t *wcsncat(wchar_t *restrict, const wchar_t *restrict, size_t);
int wcsncmp(const wchar_t *, const wchar_t *, size_t);
wchar_t *wcsncpy(wchar_t *restrict, const wchar_t *restrict, size_t);
size_t wcsnlen(const wchar_t *, size_t);
size_t wcsnrtombs(char *restrict, const wchar_t **restrict, size_t,
size_t, mbstate_t *restrict);
wchar_t *wcspbrk(const wchar_t *, const wchar_t *);
wchar_t *wcsrchr(const wchar_t *, wchar_t);
size_t wcsrtombs(char *restrict, const wchar_t **restrict,
size_t, mbstate_t *restrict);
size_t wcsspn(const wchar_t *, const wchar_t *);
wchar_t *wcsstr(const wchar_t *restrict, const wchar_t *restrict);
double wcstod(const wchar_t *restrict, wchar_t **restrict);
float wcstof(const wchar_t *restrict, wchar_t **restrict);
wchar_t *wcstok(wchar_t *restrict, const wchar_t *restrict,
wchar_t **restrict);
long wcstol(const wchar_t *restrict, wchar_t **restrict, int);
long double wcstold(const wchar_t *restrict, wchar_t **restrict);
long long wcstoll(const wchar_t *restrict, wchar_t **restrict, int);
unsigned long wcstoul(const wchar_t *restrict, wchar_t **restrict, int);
unsigned long long
wcstoull(const wchar_t *restrict, wchar_t **restrict, int);
int wcswidth(const wchar_t *, size_t);
size_t wcsxfrm(wchar_t *restrict, const wchar_t *restrict, size_t);
size_t wcsxfrm_l(wchar_t *restrict, const wchar_t *restrict,
size_t, locale_t);
int wctob(wint_t);
wctype_t wctype(const char *);
int wcwidth(wchar_t);
wchar_t *wmemchr(const wchar_t *, wchar_t, size_t);
int wmemcmp(const wchar_t *, const wchar_t *, size_t);
wchar_t *wmemcpy(wchar_t *restrict, const wchar_t *restrict, size_t);
wchar_t *wmemmove(wchar_t *, const wchar_t *, size_t);
wchar_t *wmemset(wchar_t *, wchar_t, size_t);
int wprintf(const wchar_t *restrict, ...);
int wscanf(const wchar_t *restrict, ...);
The following sections are informative.
APPLICATION USAGE
The iswblank() function was a late addition to the ISO C standard and was introduced at the same time as
the ISO C standard introduced <wctype.h>, which contains all of the isw*() functions. The Open Group Base
Specifications had previously aligned with the MSE working draft and had introduced the rest of the
isw*() functions into <wchar.h>. For backwards-compatibility, the original set of isw*() functions,
without iswblank(), are permitted (as part of the XSI option) in <wchar.h>. For maximum portability,
applications should include <wctype.h> in order to obtain declarations for the isw*() functions. This
compatibility has been made obsolescent.
RATIONALE
In the ISO C standard, the symbols referenced as XSI extensions are in <wctype.h>. Their presence here
is thus an extension.
FUTURE DIRECTIONS
None.
SEE ALSO
<ctype.h>, <locale.h>, <stdarg.h>, <stddef.h>, <stdint.h>, <stdio.h>, <stdlib.h>, <string.h>, <time.h>,
<wctype.h>
The System Interfaces volume of POSIX.1‐2017, Section 2.2, The Compilation Environment, btowc(),
confstr(), fgetwc(), fgetws(), fputwc(), fputws(), fwide(), fwprintf(), fwscanf(), getwc(), getwchar(),
iswalnum(), iswalpha(), iswcntrl(), iswctype(), iswdigit(), iswgraph(), iswlower(), iswprint(),
iswpunct(), iswspace(), iswupper(), iswxdigit(), mbrlen(), mbrtowc(), mbsinit(), mbsrtowcs(),
open_memstream(), putwc(), putwchar(), towlower(), towupper(), ungetwc(), vfwprintf(), vfwscanf(),
wcrtomb(), wcscasecmp(), wcscat(), wcschr(), wcscmp(), wcscoll(), wcscpy(), wcscspn(), wcsdup(),
wcsftime(), wcslen(), wcsncat(), wcsncmp(), wcsncpy(), wcspbrk(), wcsrchr(), wcsrtombs(), wcsspn(),
wcsstr(), wcstod(), wcstok(), wcstol(), wcstoul(), wcswidth(), wcsxfrm(), wctob(), wctype(), wcwidth(),
wmemchr(), wmemcmp(), wmemcpy(), wmemmove(), wmemset()
The Shell and Utilities volume of POSIX.1‐2017, getconf
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 .