STD::CTYPE(3cxx)

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💖 std::ctype< _CharT > — std::ctype< _CharT >(3cxx) 💖

okay so bestie, this is the std::ctype< _CharT >(3cxx) page — the primary class template ctype facet, and we are gonna go through every single detail together. no skips, no “you can figure it out,” fr fr. ✨

🌸 NAME 🌸

std::ctype< _CharT > — primary class template ctype facet.

✨ SYNOPSIS ✨

#include <locale>

Inherits std::__ctype_abstract_base< _CharT >.

Inherited by std::ctype_byname< _CharT >.

🎀 Public Types 🎀

  • typedef const int * __to_type
  • typedef _CharT char_type
  • typedef __ctype_abstract_base< _CharT >::mask mask

💅 Public Member Functions 💅

  • ctype (size_t __refs=0) — the constructor, with __refs defaulting to 0.
  • const char_type * is (const char_type *__lo, const char_type *__hi, mask *__vec) const — return a mask array.
  • bool is (mask __m, char_type __c) const — test char_type classification.
  • char narrow (char_type __c, char __dfault) const — narrow char_type to char.
  • const char_type * narrow (const char_type *__lo, const char_type *__hi, char __dfault, char *__to) const — narrow array to char array.
  • const char_type * scan_is (mask __m, const char_type *__lo, const char_type *__hi) const — find char_type matching a mask.
  • const char_type * scan_not (mask __m, const char_type *__lo, const char_type *__hi) const — find char_type not matching a mask.
  • const char_type * tolower (char_type *__lo, const char_type *__hi) const — convert array to lowercase.
  • char_type tolower (char_type __c) const — convert to lowercase.
  • const char_type * toupper (char_type *__lo, const char_type *__hi) const — convert array to uppercase.
  • char_type toupper (char_type __c) const — convert to uppercase.
  • char_type widen (char __c) const — widen char to char_type.
  • const char * widen (const char *__lo, const char *__hi, char_type *__to) const — widen array to char_type.

🦋 Static Public Attributes 🦋

  • static const mask alnum
  • static const mask alpha
  • static const mask blank
  • static const mask cntrl
  • static const mask digit
  • static const mask graph
  • static locale::id id — the facet id for ctype<char_type>
  • static const mask lower
  • static const mask print
  • static const mask punct
  • static const mask space
  • static const mask upper
  • static const mask xdigit

🧚 Protected Member Functions 🧚

  • virtual const char_type * do_is (const char_type *__lo, const char_type *__hi, mask *__vec) const — return a mask array.
  • virtual bool do_is (mask __m, char_type __c) const — test char_type classification.
  • virtual char do_narrow (char_type, char __dfault) const — narrow char_type to char.
  • virtual const char_type * do_narrow (const char_type *__lo, const char_type *__hi, char __dfault, char *__to) const — narrow char_type array to char.
  • virtual const char_type * do_scan_is (mask __m, const char_type *__lo, const char_type *__hi) const — find char_type matching mask.
  • virtual const char_type * do_scan_not (mask __m, const char_type *__lo, const char_type *__hi) const — find char_type not matching mask.
  • virtual const char_type * do_tolower (char_type *__lo, const char_type *__hi) const — convert array to lowercase.
  • virtual char_type do_tolower (char_type __c) const — convert to lowercase.
  • virtual const char_type * do_toupper (char_type *__lo, const char_type *__hi) const — convert array to uppercase.
  • virtual char_type do_toupper (char_type __c) const — convert to uppercase.
  • virtual char_type do_widen (char __c) const — widen char.
  • virtual const char * do_widen (const char *__lo, const char *__hi, char_type *__dest) const — widen char array.

🫶 Static Protected Member Functions 🫶

  • static __c_locale _S_clone_c_locale (__c_locale &__cloc) throw ()
  • static void _S_create_c_locale (__c_locale &__cloc, const char *__s, __c_locale __old=0)
  • static void _S_destroy_c_locale (__c_locale &__cloc)
  • static __c_locale _S_get_c_locale ()
  • static const char * _S_get_c_name () throw ()
  • static __c_locale _S_lc_ctype_c_locale (__c_locale __cloc, const char *__s)

🌈 Detailed Description 🌈

template<typename _CharT>
class std::ctype< _CharT >

Primary class template ctype facet.

This template class defines classification and conversion functions for character sets. It wraps cctype functionality. Ctype gets used by streams for many I/O operations.

This template provides the protected virtual functions the developer will have to replace in a derived class or specialization to make a working facet. The public functions that access them are defined in __ctype_abstract_base, to allow for implementation flexibility. See ctype<wchar_t> for an example. The functions are documented in __ctype_abstract_base.

Note: implementations are provided for all the protected virtual functions, but will likely not be useful.

🔥 Member Function Documentation 🔥

🧚 do_is — array version 🧚

template<typename _CharT > virtual const char_type * std::ctype< _CharT >::do_is (const char_type * __lo, const char_type * __hi, mask * __vec) const

[protected], [virtual]

Return a mask array. This function finds the mask for each char_type in the range [lo,hi) and successively writes it to vec. vec must have as many elements as the input.

do_is() is a hook for a derived facet to change the behavior of classifying. do_is() must always return the same result for the same input.

Parameters

  • __lo — pointer to start of range.
  • __hi — pointer to end of range.
  • __vec — pointer to an array of mask storage.

Returns

__hi.

Implements std::__ctype_abstract_base< _CharT >.

🎀 do_is — mask + char version 🎀

template<typename _CharT > virtual bool std::ctype< _CharT >::do_is (mask __m, char_type __c) const

[protected], [virtual]

Test char_type classification. This function finds a mask M for c and compares it to mask m.

do_is() is a hook for a derived facet to change the behavior of classifying. do_is() must always return the same result for the same input.

Parameters

  • __c — the char_type to find the mask of.
  • __m — the mask to compare against.

Returns

(M & __m) != 0.

Implements std::__ctype_abstract_base< _CharT >.

🦋 do_narrow — single char 🦋

template<typename _CharT > virtual char std::ctype< _CharT >::do_narrow (char_type __c, char __dfault) const

[protected], [virtual]

Narrow char_type to char. This virtual function converts the argument to char using the simplest reasonable transformation. If the conversion fails, dfault is returned instead.

do_narrow() is a hook for a derived facet to change the behavior of narrowing. do_narrow() must always return the same result for the same input.

Note: this is not what you want for codepage conversions. See codecvt for that.

Parameters

  • __c — the char_type to convert.
  • __dfault — char to return if conversion fails.

Returns

The converted char.

Implements std::__ctype_abstract_base< _CharT >.

Referenced by std::ctype< char >::narrow(), and std::ctype< char >::narrow().

🌸 do_narrow — array version 🌸

template<typename _CharT > virtual const char_type * std::ctype< _CharT >::do_narrow (const char_type * __lo, const char_type * __hi, char __dfault, char * __to) const

[protected], [virtual]

Narrow char_type array to char. This virtual function converts each char_type in the range [__lo,__hi) to char using the simplest reasonable transformation and writes the results to the destination array. For any element in the input that cannot be converted, __dfault is used instead.

do_narrow() is a hook for a derived facet to change the behavior of narrowing. do_narrow() must always return the same result for the same input.

Note: this is not what you want for codepage conversions. See codecvt for that.

Parameters

  • __lo — pointer to start of range.
  • __hi — pointer to end of range.
  • __dfault — char to use if conversion fails.
  • __to — pointer to the destination array.

Returns

__hi.

Implements std::__ctype_abstract_base< _CharT >.

💜 do_scan_is 💜

template<typename _CharT > virtual const char_type * std::ctype< _CharT >::do_scan_is (mask __m, const char_type * __lo, const char_type * __hi) const

[protected], [virtual]

Find char_type matching mask. This function searches for and returns the first char_type c in [__lo,__hi) for which is(__m,c) is true.

do_scan_is() is a hook for a derived facet to change the behavior of match searching. do_is() must always return the same result for the same input.

Parameters

  • __m — the mask to compare against.
  • __lo — pointer to start of range.
  • __hi — pointer to end of range.

Returns

Pointer to a matching char_type if found, else __hi.

Implements std::__ctype_abstract_base< _CharT >.

⭐ do_scan_not ⭐

template<typename _CharT > virtual const char_type * std::ctype< _CharT >::do_scan_not (mask __m, const char_type * __lo, const char_type * __hi) const

[protected], [virtual]

Find char_type not matching mask. This function searches for and returns a pointer to the first char_type c of [lo,hi) for which is(m,c) is false.

do_scan_is() is a hook for a derived facet to change the behavior of match searching. do_is() must always return the same result for the same input.

Parameters

  • __m — the mask to compare against.
  • __lo — pointer to start of range.
  • __hi — pointer to end of range.

Returns

Pointer to a non-matching char_type if found, else __hi.

Implements std::__ctype_abstract_base< _CharT >.

🌈 do_tolower — array version 🌈

template<typename _CharT > virtual const char_type * std::ctype< _CharT >::do_tolower (char_type * __lo, const char_type * __hi) const

[protected], [virtual]

Convert array to lowercase. This virtual function converts each char_type in the range [__lo,__hi) to lowercase if possible. Other elements remain untouched.

do_tolower() is a hook for a derived facet to change the behavior of lowercasing. do_tolower() must always return the same result for the same input.

Parameters

  • __lo — pointer to start of range.
  • __hi — pointer to end of range.

Returns

__hi.

Implements std::__ctype_abstract_base< _CharT >.

🍓 do_tolower — single char 🍓

template<typename _CharT > virtual char_type std::ctype< _CharT >::do_tolower (char_type __c) const

[protected], [virtual]

Convert to lowercase. This virtual function converts the argument to lowercase if possible. If not possible (for example, '2'), returns the argument.

do_tolower() is a hook for a derived facet to change the behavior of lowercasing. do_tolower() must always return the same result for the same input.

Parameters

  • __c — the char_type to convert.

Returns

The lowercase char_type if convertible, else __c.

Implements std::__ctype_abstract_base< _CharT >.

Referenced by std::ctype< char >::tolower(), and std::ctype< char >::tolower().

🫶 do_toupper() — the array version

template<typename _CharT > virtual const char_type * std::ctype< _CharT >::do_toupper (char_type * __lo, const char_type * __hi) const

[protected], [virtual]

Okay so bestie, this is a convert-array-to-uppercase situation. This virtual function converts each char_type in the range [__lo,__hi) to uppercase if possible. Elements it can't convert just stay untouched, no drama. 💅

do_toupper() is a hook for a derived facet to change the behavior of uppercasing. And like — hear me on this — do_toupper() must always return the same result for the same input. No cap, that's the rule.

Parameters

  • __lo — pointer to start of range.
  • __hi — pointer to end of range.

Returns — __hi. That's it, that's the whole return.

Implements std::__ctype_abstract_base< _CharT >.

✨ do_toupper() — the single-char version

template<typename _CharT > virtual char_type std::ctype< _CharT >::do_toupper (char_type __c) const

[protected], [virtual]

Convert to uppercase, one char_type at a time. This virtual function converts the char_type argument to uppercase if possible. If it's not possible (for example, '2' — like girl, '2' has no uppercase era), it returns the argument. 🙈

Same hook energy: do_toupper() is a hook for a derived facet to change the behavior of uppercasing, and do_toupper() must always return the same result for the same input.

Parameters

  • __c — the char_type to convert.

Returns — the uppercase char_type if convertible, else __c.

Implements std::__ctype_abstract_base< _CharT >.

Referenced by std::ctype< char >::toupper(), and std::ctype< char >::toupper().

🦋 do_widen() — the single-char version

template<typename _CharT > virtual char_type std::ctype< _CharT >::do_widen (char __c) const

[protected], [virtual]

Widen char. This virtual function converts the char to char_type using the simplest reasonable transformation. Lowkey iconic, highkey straightforward. ✨

do_widen() is a hook for a derived facet to change the behavior of widening, and do_widen() must always return the same result for the same input.

Note: this is not what you want for codepage conversions. See codecvt for that. Do not come for this function for codepage stuff, it's not her moment. 😭

Parameters

  • __c — the char to convert.

Returns — the converted char_type.

Implements std::__ctype_abstract_base< _CharT >.

Referenced by std::ctype< char >::widen(), and std::ctype< char >::widen().

🧚 do_widen() — the array version

template<typename _CharT > virtual const char * std::ctype< _CharT >::do_widen (const char * __lo, const char * __hi, char_type * __to) const

[protected], [virtual]

Widen char array. This function converts each char in the input to char_type using the simplest reasonable transformation. All of them. Every single one. 💖

do_widen() is a hook for a derived facet to change the behavior of widening, and again — do_widen() must always return the same result for the same input.

Note: this is not what you want for codepage conversions. See codecvt for that.

Parameters

  • __lo — pointer to start range.
  • __hi — pointer to end of range.
  • __to — pointer to the destination array.

Returns — __hi.

Implements std::__ctype_abstract_base< _CharT >.

🌸 is() — return a mask array

template<typename _CharT > const char_type * std::__ctype_abstract_base< _CharT >::is (const char_type * __lo, const char_type * __hi, mask * __vec) const

[inline], [inherited]

Return a mask array. This function finds the mask for each char_type in the range [lo,hi) and successively writes it to vec. And bestie — vec must have as many elements as the char array. Like, if it doesn't, that's on you. 🙈 It does so by returning the value of ctype<char_type>::do_is().

Parameters

  • __lo — pointer to start of range.
  • __hi — pointer to end of range.
  • __vec — pointer to an array of mask storage.

Returns — __hi.

References std::__ctype_abstract_base< _CharT >::do_is().

💜 is() — test char_type classification

template<typename _CharT > bool std::__ctype_abstract_base< _CharT >::is (mask __m, char_type __c) const

[inline], [inherited]

Test char_type classification. This function finds a mask M for __c and compares it to mask __m. It does so by returning the value of ctype<char_type>::do_is().

Parameters

  • __c — the char_type to compare the mask of.
  • __m — the mask to compare against.

Returns — (M & __m) != 0.

References std::__ctype_abstract_base< _CharT >::do_is().

Referenced by std::time_get< _CharT, _InIter >::get().

🎀 narrow() — char_type down to char

template<typename _CharT > char std::__ctype_abstract_base< _CharT >::narrow (char_type __c, char __dfault) const

[inline], [inherited]

Narrow char_type to char. This function converts the char_type to char using the simplest reasonable transformation. If the conversion fails, dfault is returned instead — she's got a backup plan bestie, she's prepared. 🫶 It does so by returning ctype<char_type>::do_narrow(__c).

Note: this is not what you want for codepage conversions. See codecvt for that.

Parameters

  • __c — the char_type to convert.
  • __dfault — char to return if conversion fails.

Returns — the converted char.

References std::__ctype_abstract_base< _CharT >::do_narrow().

Referenced by std::time_get< _CharT, _InIter >::do_get_year(), std::time_get< _CharT, _InIter >::get(), and std::time_put< _CharT, _OutIter >::put().

⭐ narrow() — the array version

template<typename _CharT > const char_type * std::__ctype_abstract_base< _CharT >::narrow (const char_type * __lo, const char_type * __hi, char __dfault, char * __to) const

[inline], [inherited]

Narrow array to char array. This function converts each char_type in the input to char using the simplest reasonable transformation and writes the results to the destination array. For any char_type in the input that cannot be converted, __dfault is used instead. It does so by returning ctype<char_type>::do_narrow(__lo, __hi, __dfault, __to).

Note: this is not what you want for codepage conversions. See codecvt for that.

Parameters

  • __lo — pointer to start of range.
  • __hi — pointer to end of range.
  • __dfault — char to use if conversion fails.
  • __to — pointer to the destination array.

Returns — __hi.

References std::__ctype_abstract_base< _CharT >::do_narrow().

🔥 scan_is() — find char_type matching a mask

template<typename _CharT > const char_type * std::__ctype_abstract_base< _CharT >::scan_is (mask __m, const char_type * __lo, const char_type * __hi) const

[inline], [inherited]

Find char_type matching a mask. This function searches for and returns the first char_type c in [lo,hi) for which is(m,c) is true. It does so by returning ctype<char_type>::do_scan_is().

Parameters

  • __m — the mask to compare against.
  • __lo — pointer to start of range.
  • __hi — pointer to end of range.

Returns — pointer to matching char_type if found, else __hi.

References std::__ctype_abstract_base< _CharT >::do_scan_is().

🌈 scan_not() — find char_type NOT matching a mask

template<typename _CharT > const char_type * std::__ctype_abstract_base< _CharT >::scan_not (mask __m, const char_type * __lo, const char_type * __hi) const

[inline], [inherited]

Find char_type not matching a mask. This function searches for and returns the first char_type c in [lo,hi) for which is(m,c) is false. The opposite girlie of scan_is(), we love a duo. ✨ It does so by returning ctype<char_type>::do_scan_not().

Parameters

  • __m — the mask to compare against.
  • __lo — pointer to first char in range.
  • __hi — pointer to end of range.

Returns — pointer to non-matching char if found, else __hi.

References std::__ctype_abstract_base< _CharT >::do_scan_not().

💀 tolower() — the array version

template<typename _CharT > const char_type * std::__ctype_abstract_base< _CharT >::tolower (char_type * __lo, const char_type * __hi) const

[inline], [inherited]

Convert array to lowercase. This function converts each char_type in the range [__lo,__hi) to lowercase if possible. Other elements remain untouched. It does so by returning ctype<char_type>:: do_tolower(__lo, __hi).

Parameters

  • __lo — pointer to start of range.
  • __hi — pointer to end of range.

Returns — __hi.

References std::__ctype_abstract_base< _CharT >::do_tolower().

🍓 tolower() — the single-char version

template<typename _CharT > char_type std::__ctype_abstract_base< _CharT >::tolower (char_type __c) const

[inline], [inherited]

Convert to lowercase. This function converts the argument to lowercase if possible. If not possible (for example, '2'), returns the argument. It does so by returning ctype<char_type>::do_tolower(c).

Parameters

  • __c — the char_type to convert.

Returns — the lowercase char_type if convertible, else __c.

References std::__ctype_abstract_base< _CharT >::do_tolower().

Referenced by std::time_get< _CharT, _InIter >::get().

👑 toupper() — the array version

template<typename _CharT > const char_type * std::__ctype_abstract_base< _CharT >::toupper (char_type * __lo, const char_type * __hi) const

[inline], [inherited]

Convert array to uppercase. This function converts each char_type in the range [lo,hi) to uppercase if possible. Other elements remain untouched. It does so by returning ctype<char_type>:: do_toupper(lo, hi).

Parameters

  • __lo — pointer to start of range.
  • __hi — pointer to end of range.

Returns — __hi.

References std::__ctype_abstract_base< _CharT >::do_toupper().

💅 toupper() — the single-char version

template<typename _CharT > char_type std::__ctype_abstract_base< _CharT >::toupper (char_type __c) const

[inline], [inherited]

Convert to uppercase. This function converts the argument to uppercase if possible. If not possible (for example, '2'), returns the argument. It does so by returning ctype<char_type>::do_toupper().

Parameters

  • __c — the char_type to convert.

Returns — the uppercase char_type if convertible, else __c.

References std::__ctype_abstract_base< _CharT >::do_toupper().

Referenced by std::time_get< _CharT, _InIter >::get().

🐛 widen() — char up to char_type

template<typename _CharT > char_type std::__ctype_abstract_base< _CharT >::widen (char __c) const

[inline], [inherited]

Widen char to char_type. This function converts the char argument to char_type using the simplest reasonable transformation. It does so by returning ctype<char_type>::do_widen(c).

Note: this is not what you want for codepage conversions. See codecvt for that.

Parameters

  • __c — the char to convert.

Returns — the converted char_type.

References std::__ctype_abstract_base< _CharT >::do_widen().

Referenced by std::money_get< _CharT, _InIter >::do_get(), std::time_get< _CharT, _InIter >::do_get(), std::money_put< _CharT, _OutIter >::do_put(), and std::time_put< _CharT, _OutIter >::do_put(). She's booked and busy fr fr. 💖

🌟 widen() — the array version

template<typename _CharT > const char * std::__ctype_abstract_base< _CharT >::widen (const char * __lo, const char * __hi, char_type * __to) const

[inline], [inherited]

Widen array to char_type. This function converts each char in the input to char_type using the simplest reasonable transformation. It does so by returning ctype<char_type>::do_widen(c).

Note: this is not what you want for codepage conversions. See codecvt for that.

Parameters

  • __lo — pointer to start of range.
  • __hi — pointer to end of range.
  • __to — pointer to the destination array.

Returns — __hi.

References std::__ctype_abstract_base< _CharT >::do_widen().

🎀 Member Data Documentation 🎀

💜 id

template<typename _CharT > locale::id std::ctype< _CharT >::id

[static]

The facet id for ctype<char_type>. That's her whole thing. The identity. The main character identifier. 👑

👑 AUTHOR 👑

Okay so real talk — no human wrote this one, bestie. It was generated automatically by Doxygen for libstdc++ from the source code. Which is honestly iconic of it: the docs wrote themselves, the source is the moment, periodt. 💅✨

So like… don't @ the author, because there isn't one to @. The code speaks, Doxygen transcribes, we read. That's the whole vibe. 🫶

That's a wrap on std::ctype< _CharT >, bestie — go forth and classify those characters. 🌸 This page is served up courtesy of libstdc++ and it's filed under std::ctype< _CharT >(3cxx) in the man-page universe, so that's the tag you'll see on the tin. Ngl, this one's a Doxygen-generated original straight from the source code, so if you need the receipts, the code is the receipts. 💖 🎀 🦋

📦 where this page comes from