std::basic_ios::init(3)

✨ NAME ✨

std::basic_ios::init — std::basic_ios::init

okay so this is the manual page for std::basic_ios::init(3) from the C++ Standard Libary manual, and it's giving two-stage initialization realness. 🎀

🌀 Synopsis 🌀

protected:
void init( std::basic_streambuf<CharT,Traits>* sb );

This one sets the associated stream buffer to sb and initializes the internal state. Slay. 💅

The postconditions are as follows 💖

• rdbuf() — sb
• tie() — null pointer
• rdstate() — goodbit if sb is not a null pointer, otherwise badbit
• exceptions() — goodbit
• flags() — skipws | dec
• width() — 0
• precision() — 6
• fill() — widen(' ')
• getloc() — a copy of the value returned by std::locale()

This member function is protected: it is called by the constructors of the derived stream classes std::basic_istream and std::basic_ostream once the associated stream buffer is known. 🫶

Until this function is called, every member function (including the destructor) of the default-constructed std::basic_ios invokes undefined behavior. No cap, that's the scary part. 😭

Also note that basic_ios is a virtual base class, and therefore its constructor is not called by the constructors of those directly derived classes — which is why two-stage initialization is necessary. Iykyk. 🦋

🌸 Parameters 🌸

• sb — stream buffer to associate to.

👀 See also 👀

• constructor — constructs the object (public member function) ✨

💖 source/version: http://cppreference.com · date: 2024.06.10 · page: std::basic_ios::init(3) — love u bestie, go init something safely 💅🎀