std::basic_...buf::setbuf(3)

💖 std::basic_...buf::setbuf(3) 💖

okay bestie, welcome to this page from the C++ Standard Libary manual — yes, that's the spelling up there, and we're keeping it because it's iconic 😭💅. This is the std::basic_stringbuf::setbuf page, and it's very much giving "protected virtual buffer behavior, read carefully."

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🌸 NAME 🌸

std::basic_stringbuf::setbuf - std::basic_stringbuf::setbuf

✨ Synopsis ✨

          protected:
          virtual std::basic_streambuf<CharT, Traits>* setbuf( char_type* s,
       std::streamsize
          n )

If s is a null pointer and n is zero, this function has no effect. literally nothing, no drama 💀.

Otherwise, bestie, the effect is implementation-defined: some implementations do nothing, while some implementations clear the std::string member currently used as the buffer and begin using the user-supplied character array of size n, whose first element is pointed to by s, as the buffer and the input/output character sequence. it's giving "your mileage may vary" energy. 🦋

This function is protected virtual, so it may only be called through pubsetbuf() or from member functions of a user-defined class derived from std::basic_stringbuf. no random main-character calls from outside, iykyk. 🔒

🎀 Parameters 🎀

• s — pointer to the first CharT in the user-provided buffer or null
• n — the number of CharT elements in the user-provided buffer or zero

🫶 Return value 🫶

this — that's the whole return value, bestie. periodt. 💅

👑 Notes 👑

ngl, the notes say the deprecated stream buffer std::strstreambuf or the boost.IOStreams device boost::basic_array may be used to implement I/O buffering over a user-provided char array in portable manner. deprecated, but still mentioned; respect the lore. 💀

🍓 Example 🍓

Test for the stringstream's setbuf functionality.

The page says // Run this code, and here's the code exactly:

        #include <iostream>
        #include <sstream>

        int main()
        {
            std::ostringstream ss;
            char c[1024] = {};
            ss.rdbuf()->pubsetbuf(c, 1024);
            ss << 3.14 << '\n';
            std::cout << c << '\n';
        }

🖥️ Output:

        3.14 (on GNU g++/libstdc++ and SunPro C++/roguewave)
        <nothing> (on MS Visual Studio 2010, SunPro C++/stlport4,
       CLang++/libc++)

👀 See also 👀

• pubsetbuf invokes setbuf() (public member function of std::basic_streambuf<CharT,Traits>)

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mwah 💋 — this page came from http://cppreference.com, dated 2024.06.10, and it's the std::basic_...buf::setbuf(3) page. periodt. 🌈✨