std::basic_...ce::crbegin(3)

🦋 std::basic_stacktrace::rbegin / std::basic_stacktrace::crbegin 🦋

Okay bestie, this page is from the C++ Standard Libary manual (that's the manual name as it appears, spelling included 💅), and the page title is std::basic_...ce::crbegin(3). We're talking about rbegin and crbegin on std::basic_stacktrace, and yes, both are since C++23. Periodt.

🎀 NAME 🎀

std::basic_stacktrace::rbegin,std::basic_stacktrace::crbegin — and then, literally, the exact same name again: std::basic_stacktrace::rbegin,std::basic_stacktrace::crbegin. No extra lore, that's the whole NAME section.

✨ Synopsis ✨

Here's the signature situation, bestie:

const_reverse_iterator rbegin()  const noexcept; (1) (since C++23)
const_reverse_iterator crbegin() const noexcept; (2) (since C++23)

So both of these return a reverse iterator to the first entry of the reversed basic_stacktrace. It corresponds to the last entry of the original basic_stacktrace. And if the basic_stacktrace is empty, the returned iterator is equal to rend().

The original page also drops a diagram named range-rbegin-rend.svg — yes, that's the literal filename — to show the rbegin/rend range vibe. 🫶

🌸 Parameters 🌸

(none) — not a single argument, not one optional extra. It's giving no-arg icon behavior. 💅

💖 Return value 💖

Reverse iterator to the first entry. That's the whole return value, and it ate. ✨

🎀 Complexity 🎀

Constant. No cap, constant. 🧚

🔥 Example 🔥

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

#include <algorithm>
#include <iostream>
#include <stacktrace>

int main()
{
    auto trace       = std::stacktrace::current();
    auto empty_trace = std::stacktrace{};

    // Print stacktrace.
    std::for_each(trace.rbegin(), trace.rend(),
                  [](const auto& f) { std::cout << f << '\n'; });

    if (empty_trace.rbegin() == empty_trace.rend())
        std::cout << "stacktrace 'empty_trace' is indeed empty.\n";
}

Possible output:

0x0000000000402A29 in ./prog.exe
__libc_start_main in /lib/x86_64-linux-gnu/libc.so.6
0x0000000000402BA5 in ./prog.exe
stacktrace 'empty_trace' is indeed empty.

🌈 See also 🌈

• rend — returns a reverse iterator to the end
• crend — (public member function)

And that's the whole page, bestie! Source/version/date: http://cppreference.com, 2024.06.10, page std::basic_...ce::crbegin(3). Mwah 💋✨