std::cout,std::wcout(3)

💖 std::cout,std::wcout 💖

okay bestie, this is straight from the C++ Standard Libary, section 3 — and it’s literally the page for std::cout,std::wcout. no cap, these two are the main-character output girlies of C++. 💅

💅 NAME 💅

std::cout,std::wcout — literally std::cout,std::wcout. that’s the name, that’s the vibe. ✨

✨ Synopsis ✨

Defined in header <iostream>:

extern std::ostream cout;    (1)
extern std::wostream wcout;  (2)

The global objects std::cout and std::wcout control output to a stream buffer of implementation-defined type (derived from std::streambuf), associated with the standard C output stream stdout. 🫶

These objects are guaranteed to be initialized during or before the first time an object of type std::ios_base::Init is constructed and are available for use in the constructors and destructors of static objects with ordered initialization (as long as <iostream> is included before the object is defined). 💖

Unless std::ios_base::sync_with_stdio(false) has been issued, it is safe to concurrently access these objects from multiple threads for both formatted and unformatted output. 🔥

By specification of std::cin, std::cin.tie() returns &std::cout. This means that any input operation on std::cin executes std::cout.flush() (via std::basic_istream::sentry's constructor). Similarly, std::wcin.tie() returns &std::wcout. 😭

By specification of std::cerr, std::cerr.tie() returns &std::cout. This means that any output operation on std::cerr executes std::cout.flush() (via std::basic_ostream::sentry's constructor). Similarly, std::wcerr.tie() returns &std::wcout. (since C++11) 💀

💖 Notes 💖

The c in the name refers to "character" (stroustrup.com FAQ); cout means "character output" and wcout means "wide character output". 🎀

Because dynamic initialization of templated variables are unordered, it is not guaranteed that std::cout has been initialized to a usable state before the initialization of such variables begins, unless an object of type std::ios_base::Init has been constructed. 🙈

🎀 Example 🎀

// Run this code

#include <iostream>

struct Foo
{
    int n;
    Foo()
    {
        std::cout << "static constructor\n";
    }
    ~Foo()
    {
        std::cout << "static destructor\n";
    }
};

Foo f; // static object

int main()
{
    std::cout << "main function\n";
}

🌈 Output: 🌈

static constructor
main function
static destructor

🦋 See also 🦋

• Init — initializes standard stream objects (public member class of std::ios_base)
• cerr — writes to the standard C error stream stderr, unbuffered
• wcerr — (global object)
• clog — writes to the standard C error stream stderr
• wclog — (global object)
• stdin — expression of type FILE* associated with the input stream
• stdout — expression of type FILE* associated with the output stream
• stderr — expression of type FILE* associated with the error output stream (macro constant)

signed, sealed, and slayed by cppreference.com — 2024.06.10 — page std::cout,std::wcout(3). 💜👑