Standard library header <cwchar>

This header was originally in the C standard library as <wchar.h>.

This header is part of the null-terminated wide and multibyte strings libraries. It also provides some C-style I/O functions and conversion from C-style Date.

Macros

Types

Functions

Notes

• NULL is also defined in the following headers:
  • <cstddef>
  • <cstring>
  • <ctime>
  • <clocale>
  • <cstdio>
• std::size_t is also defined in the following headers:
  • <cstddef>
  • <ctime>
  • <cstdio>
• std::wint_t is also defined in the following headers:
  • <cwctype>
• std::tm is also defined in the following headers:
  • <ctime>

Synopsis

#define __STDC_VERSION_WCHAR_H__ 202311L

namespace std {
  using size_t = /* implementation-defined */; // freestanding
  using mbstate_t = /* see description */;     // freestanding
  using wint_t = /* see description */;        // freestanding

  struct tm;

  int fwprintf(FILE* stream, const wchar_t* format, ...);
  int fwscanf(FILE* stream, const wchar_t* format, ...);
  int swprintf(wchar_t* s, size_t n, const wchar_t* format, ...);
  int swscanf(const wchar_t* s, const wchar_t* format, ...);
  int vfwprintf(FILE* stream, const wchar_t* format, va_list arg);
  int vfwscanf(FILE* stream, const wchar_t* format, va_list arg);
  int vswprintf(wchar_t* s, size_t n, const wchar_t* format, va_list arg);
  int vswscanf(const wchar_t* s, const wchar_t* format, va_list arg);
  int vwprintf(const wchar_t* format, va_list arg);
  int vwscanf(const wchar_t* format, va_list arg);
  int wprintf(const wchar_t* format, ...);
  int wscanf(const wchar_t* format, ...);
  wint_t fgetwc(FILE* stream);
  wchar_t* fgetws(wchar_t* s, int n, FILE* stream);
  wint_t fputwc(wchar_t c, FILE* stream);
  int fputws(const wchar_t* s, FILE* stream);
  int fwide(FILE* stream, int mode);
  wint_t getwc(FILE* stream);
  wint_t getwchar();
  wint_t putwc(wchar_t c, FILE* stream);
  wint_t putwchar(wchar_t c);
  wint_t ungetwc(wint_t c, FILE* stream);
  double wcstod(const wchar_t* nptr, wchar_t** endptr);
  float wcstof(const wchar_t* nptr, wchar_t** endptr);
  long double wcstold(const wchar_t* nptr, wchar_t** endptr);
  long int wcstol(const wchar_t* nptr, wchar_t** endptr, int base);
  long long int wcstoll(const wchar_t* nptr, wchar_t** endptr, int base);
  unsigned long int wcstoul(const wchar_t* nptr, wchar_t** endptr, int base);
  unsigned long long int wcstoull(const wchar_t* nptr, wchar_t** endptr, int base);
  wchar_t* wcscpy(wchar_t* s1, const wchar_t* s2);                // freestanding
  wchar_t* wcsncpy(wchar_t* s1, const wchar_t* s2, size_t n);     // freestanding
  wchar_t* wmemcpy(wchar_t* s1, const wchar_t* s2, size_t n);     // freestanding
  wchar_t* wmemmove(wchar_t* s1, const wchar_t* s2, size_t n);    // freestanding
  wchar_t* wcscat(wchar_t* s1, const wchar_t* s2);                // freestanding
  wchar_t* wcsncat(wchar_t* s1, const wchar_t* s2, size_t n);     // freestanding
  int wcscmp(const wchar_t* s1, const wchar_t* s2);               // freestanding
  int wcscoll(const wchar_t* s1, const wchar_t* s2);
  int wcsncmp(const wchar_t* s1, const wchar_t* s2, size_t n);    // freestanding
  size_t wcsxfrm(wchar_t* s1, const wchar_t* s2, size_t n);
  int wmemcmp(const wchar_t* s1, const wchar_t* s2, size_t n);    // freestanding
  const wchar_t* wcschr(const wchar_t* s, wchar_t c);             // freestanding
  wchar_t* wcschr(wchar_t* s, wchar_t c);                         // freestanding
  size_t wcscspn(const wchar_t* s1, const wchar_t* s2);           // freestanding
  const wchar_t* wcspbrk(const wchar_t* s1, const wchar_t* s2);   // freestanding
  wchar_t* wcspbrk(wchar_t* s1, const wchar_t* s2);               // freestanding
  const wchar_t* wcsrchr(const wchar_t* s, wchar_t c);            // freestanding
  wchar_t* wcsrchr(wchar_t* s, wchar_t c);                        // freestanding
  size_t wcsspn(const wchar_t* s1, const wchar_t* s2);            // freestanding
  const wchar_t* wcsstr(const wchar_t* s1, const wchar_t* s2);    // freestanding
  wchar_t* wcsstr(wchar_t* s1, const wchar_t* s2);                // freestanding
  wchar_t* wcstok(wchar_t* s1, const wchar_t* s2, wchar_t** ptr); // freestanding
  const wchar_t* wmemchr(const wchar_t* s, wchar_t c, size_t n);  // freestanding
  wchar_t* wmemchr(wchar_t* s, wchar_t c, size_t n);              // freestanding
  size_t wcslen(const wchar_t* s);                                // freestanding
  wchar_t* wmemset(wchar_t* s, wchar_t c, size_t n);              // freestanding
  size_t wcsftime(wchar_t* s, size_t maxsize, const wchar_t* format, const tm* timeptr);
  wint_t btowc(int c);
  int wctob(wint_t c);

  // multibyte / wide string and character conversion functions
  int mbsinit(const mbstate_t* ps);
  size_t mbrlen(const char* s, size_t n, mbstate_t* ps);
  size_t mbrtowc(wchar_t* pwc, const char* s, size_t n, mbstate_t* ps);
  size_t wcrtomb(char* s, wchar_t wc, mbstate_t* ps);
  size_t mbsrtowcs(wchar_t* dst, const char** src, size_t len, mbstate_t* ps);
  size_t wcsrtombs(char* dst, const wchar_t** src, size_t len, mbstate_t* ps);
}

#define NULL /* implementation-defined */ // freestanding
#define WCHAR_MAX /* see description */   // freestanding
#define WCHAR_MIN /* see description */   // freestanding
#define WEOF /* see description */        // freestanding
#define WCHAR_WIDTH /* see description */ // freestanding

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.