std::recurs...x::try_lock(3)

🦋 std::recurs...x::try_lock(3) 🦋

okay so welcome to the C++ Standard Libary page for std::recursive_mutex::try_lock — yes bestie, the header abbreviates it as std::recurs...x::try_lock(3), and we are officially in try-lock territory 💅✨

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🌸 NAME 🌸

std::recursive_mutex::try_lock — std::recursive_mutex::try_lock

that's the whole name, no cap 🫶

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✨ Synopsis ✨

bool try_lock() noexcept;  (since C++11)

Tries to lock the mutex. Returns immediately. On successful lock acquisition returns true, otherwise returns false.

This function is allowed to fail spuriously and return false even if the mutex is not currently locked by any other thread. so yeah, if you get false, it's not automatically a skill issue 😭

A thread may call try_lock on a recursive mutex repeatedly. Successful calls to try_lock increment the ownership count: the mutex will only be released after the thread makes a matching number of calls to unlock.

The maximum number of levels of ownership is unspecified. A call to try_lock will return false if this number is exceeded.

Prior unlock() operation on the same mutex synchronizes-with (as defined in std::memory_order) this operation if it returns true. Note that prior lock() does not synchronize with this operation if it returns false.

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💖 Parameters 💖

(none) — literally no parameters. zero. zilch. iconic 💅

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🎀 Return value 🎀

true if the lock was acquired successfully, otherwise false. periodt 💖

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🦋 Exceptions 🦋

Throws nothing. not a single exception. slay ✨

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🌈 Example 🌈

// Run this code — okay bestie, copy/paste exactly:

#include <iostream>
#include <mutex>

int main()
{
    std::recursive_mutex test;
    if (test.try_lock())
    {
        std::cout << "lock acquired\n";
        test.unlock();
    }
    else
        std::cout << "lock not acquired\n";

    test.lock();
    // non-recursive mutex would return false from try_lock now
    if (test.try_lock())
    {
        std::cout << "lock acquired\n";
        test.unlock();
    }
    else
        std::cout << "lock not acquired\n";

    test.unlock();
}

🌟 Output 🌟

lock acquired
lock acquired

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👀 See also 👀

• lock — locks the mutex, blocks if the mutex is not available (public member function)
• unlock — unlocks the mutex (public member function)
• C documentation for mtx_trylock

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source/version/date check bestie: http://cppreference.com · 2024.06.10 · page tag std::recurs...x::try_lock(3) — that's the footer, folded into this cute little sign-off 🫶✨💖