STD::__CODECVT_ABSTRACT_BASE(3)

✨ NAME ✨

okay bestie, so this is std::__codecvt_abstract_base< _InternT, _ExternT, _StateT > — the common base for codecvt functions 💖

and like, this whole thing lives in the Library Functions Manual (the libstdc++ one, iykyk), so consider this your backstage pass 🎀

---

🦋 SYNOPSIS 🦋

#include <locale>

Inherits std::locale::facet, and std::codecvt_base.

Inherited by std::codecvt< char_type, char, __state_type >, and std::codecvt< _InternT, _ExternT, _StateT >.

🌸 Public Types 🌸

• typedef _ExternT extern_type — the outside-world char type, the one the rest of the world speaks 🫶
• typedef _InternT intern_type — the inside-our-house char type, the one we speak ✨
• typedef codecvt_base::result result — the result enum, borrowed straight from codecvt_base 💅
• typedef _StateT state_type — the state type, for when conversion has ✨memory✨

💅 Public Member Functions 💅

• bool always_noconv () const throw () — does this facet just... not convert? asks the question, throws nothing 👑
• int encoding () const throw () — how many extern chars per intern char, basically. throws nothing 🔥
• result in (state_type &__state, const extern_type *__from, const extern_type *__from_end, const extern_type *&__from_next, intern_type *__to, intern_type *__to_end, intern_type *&__to_next) const — Convert from external to internal character set. the glow-up goes from extern_type to intern_type 🦋
• int length (state_type &__state, const extern_type *__from, const extern_type *__end, size_t __max) const — how long is this input, in intern chars, max __max of them ⭐
• int max_length () const throw () — the absolute most extern chars one intern char could ever need. throws nothing 💀
• result out (state_type &__state, const intern_type *__from, const intern_type *__from_end, const intern_type *&__from_next, extern_type *__to, extern_type *__to_end, extern_type *&__to_next) const — Convert from internal to external character set. the other direction, no cap 🌈
• result unshift (state_type &__state, extern_type *__to, extern_type *__to_end, extern_type *&__to_next) const — Reset conversion state. getting that state back to factory settings 🎀

🧚 Protected Member Functions 🧚

• __codecvt_abstract_base (size_t __refs=0) — the constructor, refs default to 0, iconic
• virtual bool do_always_noconv () const throw () =0 — pure virtual, you must implement it, no exceptions (literally, it's throw ()) 🙈
• virtual int do_encoding () const throw () =0 — pure virtual, implement it or perish 💀
• virtual result do_in (state_type &__state, const extern_type *__from, const extern_type *__from_end, const extern_type *&__from_next, intern_type *__to, intern_type *__to_end, intern_type *&__to_next) const =0 — pure virtual, the actual external→internal work 🌸
• virtual int do_length (state_type &, const extern_type *__from, const extern_type *__end, size_t __max) const =0 — pure virtual, note the first param is unnamed, it said "we don't need to name it, we know what it is" 💅
• virtual int do_max_length () const throw () =0 — pure virtual, max length, throws nothing 👑
• virtual result do_out (state_type &__state, const intern_type *__from, const intern_type *__from_end, const intern_type *&__from_next, extern_type *__to, extern_type *__to_end, extern_type *&__to_next) const =0 — Convert from internal to external character set. pure virtual 🔥
• virtual result do_unshift (state_type &__state, extern_type *__to, extern_type *__to_end, extern_type *&__to_next) const =0 — pure virtual, reset that state ✨

⭐ Static Protected Member Functions ⭐

• static __c_locale _S_clone_c_locale (__c_locale &__cloc) throw () — clone the C locale, throws nothing 🫶
• static void _S_create_c_locale (__c_locale &__cloc, const char *__s, __c_locale __old=0) — make a C locale from __s, with __old defaulting to 0 🎀
• static void _S_destroy_c_locale (__c_locale &__cloc) — bye bye locale, destroy it 💅
• static __c_locale _S_get_c_locale () — grab the C locale 🌸
• static const char * _S_get_c_name () throw () — get the C locale's name, throws nothing ⭐
• static __c_locale _S_lc_ctype_c_locale (__c_locale __cloc, const char *__s) — build an LC_CTYPE-flavoured C locale from __s 🦋

---

🔥 Detailed Description 🔥

template<typename _InternT, typename _ExternT, typename _StateT>
    class std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >

"Common base for codecvt functions."

no fr, that's the vibe. so here's the tea ☕:

This template class provides implementations of the public functions that forward to the protected virtual functions. 💫

This template also provides abstract stubs for the protected virtual functions. (stubs = "you go implement that, bestie, i'm just the blueprint") 🎀

---

🌈 Member Function Documentation 🌈

💜 do_out

template<typename _InternT, typename _ExternT, typename _StateT> virtual
    result std::__codecvt_abstract_base< _InternT, _ExternT, _StateT
    >::do_out (state_type & __state, const intern_type * __from, const
    intern_type * __from_end, const intern_type *& __from_next, extern_type
    * __to, extern_type * __to_end, extern_type *& __to_next) const
    [protected],  [pure virtual]

Convert from internal to external character set. Converts input string of intern_type to output string of extern_type. This function is a hook for derived classes to change the value returned. 🪝✨

See also

out for more information.

Implemented in std::codecvt< _InternT, _ExternT, _StateT >, std::codecvt< _Elem, char, mbstate_t >, std::codecvt< _InternT, _ExternT, encoding_state >, std::codecvt< char, char, mbstate_t >, std::codecvt< char16_t, char, mbstate_t >, std::codecvt< char32_t, char, mbstate_t >, and std::codecvt< wchar_t, char, mbstate_t >. 👑

Referenced by out().

---

💙 in

template<typename _InternT, typename _ExternT, typename _StateT> result
    std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::in
    (state_type & __state, const extern_type * __from, const extern_type *
    __from_end, const extern_type *& __from_next, intern_type * __to,
    intern_type * __to_end, intern_type *& __to_next) const [inline]

Convert from external to internal character set. Converts input string of extern_type to output string of intern_type. This is analogous to mbsrtowcs. It does this by calling codecvt::do_in. 🦋

The source and destination character sets are determined by the facet's locale, internal and external types. 🌸

The characters in [from,from_end) are converted and written to [to,to_end). from_next and to_next are set to point to the character following the last successfully converted character, respectively. If the result needed no conversion, from_next and to_next are not affected. ⭐

The state argument should be initialized if the input is at the beginning and carried from a previous call if continuing conversion. There are no guarantees about how state is used. (no cap, that's literally what it says 😭)

The result returned is a member of codecvt_base::result. If all the input is converted, returns codecvt_base::ok. If no conversion is necessary, returns codecvt_base::noconv. If the input ends early or there is insufficient space in the output, returns codecvt_base::partial. Otherwise the conversion failed and codecvt_base::error is returned. 💀

Parameters

• __state — Persistent conversion state data.
• __from — Start of input.
• __from_end — End of input.
• __from_next — Returns start of unconverted data.
• __to — Start of output buffer.
• __to_end — End of output buffer.
• __to_next — Returns start of unused output area.

Returns

codecvt_base::result.

---

💖 out

template<typename _InternT, typename _ExternT, typename _StateT> result
    std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::out
    (state_type & __state, const intern_type * __from, const intern_type *
    __from_end, const intern_type *& __from_next, extern_type * __to,
    extern_type * __to_end, extern_type *& __to_next) const [inline]

Convert from internal to external character set. Converts input string of intern_type to output string of extern_type. This is analogous to wcsrtombs. It does this by calling codecvt::do_out. 🔥

The source and destination character sets are determined by the facet's locale, internal and external types. 🌸

The characters in [from,from_end) are converted and written to [to,to_end). from_next and to_next are set to point to the character following the last successfully converted character, respectively. If the result needed no conversion, from_next and to_next are not affected. ⭐

The state argument should be initialized if the input is at the beginning and carried from a previous call if continuing conversion. There are no guarantees about how state is used. (same energy as before, it's giving "trust me bro" 🙈)

The result returned is a member of codecvt_base::result. If all the input is converted, returns codecvt_base::ok. If no conversion is necessary, returns codecvt_base::noconv. If the input ends early or there is insufficient space in the output, returns codecvt_base::partial. Otherwise the conversion failed and codecvt_base::error is returned. 💀

Parameters

• __state — Persistent conversion state data.
• __from — Start of input.
• __from_end — End of input.
• __from_next — Returns start of unconverted data.
• __to — Start of output buffer.
• __to_end — End of output buffer.
• __to_next — Returns start of unused output area.

Returns

codecvt_base::result.

References do_out().

---

🎀 unshift

template<typename _InternT, typename _ExternT, typename _StateT> result
    std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::unshift
    (state_type & __state, extern_type * __to, extern_type * __to_end,
    extern_type *& __to_next) const [inline]

Reset conversion state. Writes characters to output that would restore state to initial conditions. The idea is that if a partial conversion occurs, then the converting the characters written by this function would leave the state in initial conditions, rather than partial conversion state. It does this by calling codecvt::do_unshift(). ✨

For example, if 4 external characters always converted to 1 internal character, and input to in() had 6 external characters with state saved, this function would write two characters to the output and set the state to initialized conditions. 🧠✨

The source and destination character sets are determined by the facet's locale, internal and external types. 🌸

The result returned is a member of codecvt_base::result. If the state could be reset and data written, returns codecvt_base::ok. If no conversion is necessary, returns codecvt_base::noconv. If the output has insufficient space, returns codecvt_base::partial. Otherwise the reset failed and codecvt_base::error is returned. 💀

Parameters

• __state — Persistent conversion state data.
• __to — Start of output buffer.
• __to_end — End of output buffer.
• __to_next — Returns start of unused output area.

Returns

codecvt_base::result.

---

👑 Author 👑

Generated automatically by Doxygen for libstdc++ from the source code. so no, a human did not hand-write this beautiful mess, the robots did 🤖💅

---

and that's the whole page bestie!! it's libstdc++, it's the Library Functions Manual, and the source is the source code itself — generated automatically by Doxygen for libstdc++. go forth and convert characters responsibly 🦋💖✨