From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 12C263858D3C; Mon, 28 Nov 2022 08:40:45 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 12C263858D3C
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1669624845;
	bh=yQUMGkC44lBTcpnm7XXTnxZCJccYZVxPMFWQPkpGupk=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=TTDcSO18E7iwQ5BJ41bU8DlT75+sbRcN0OKmZR9x2VkXYznjfR4wgEkaHTdc3q3qg
	 JWHWSttlNp0NUJPlhXFQijWxcZUqfMMk1V56MrykbcbQT7/9kGLOugLEY6f16JmWk7
	 G1OziLg8mTtX6QZfgIhPJbmctTBsj+PT8VeHeYeo=
From: "lukaszcz18 at wp dot pl" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/107886] Problem witch std::latch,
 std::binary_semaphores in C++20
Date: Mon, 28 Nov 2022 08:40:42 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: libstdc++
X-Bugzilla-Version: 11.3.1
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: lukaszcz18 at wp dot pl
X-Bugzilla-Status: WAITING
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-107886-4-N2uaaLUiDa@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-107886-4@http.gcc.gnu.org/bugzilla/>
References: <bug-107886-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107886

--- Comment #8 from Jamaika <lukaszcz18 at wp dot pl> ---
First lesson on the page https://www.modernescpp.com/index.php/latches-in-c=
-20
I use GCC from 11.3.1 to 13.0.0 20221124
```
// workers.cpp

#include <iostream>
#include <latch>
#include <mutex>
#include <thread>

std::latch workDone(6);
std::mutex coutMutex;

void synchronizedOut(const std::string& s) {
    std::lock_guard<std::mutex> lo(coutMutex);
    std::cout << s;
}

class Worker {
 public:
    Worker(std::string n): name(n) { };

    void operator() () {
        synchronizedOut(name + ": " + "Work done!\n");
        workDone.arrive_and_wait();  // wait until all work is done  (1)
        synchronizedOut(name + ": " + "See you tomorrow!\n");
    }
 private:
    std::string name;
};

int main() {

    std::cout << '\n';

    Worker herb("  Herb");
    std::thread herbWork(herb);

    Worker scott("    Scott");
    std::thread scottWork(scott);

    Worker bjarne("      Bjarne");
    std::thread bjarneWork(bjarne);

    Worker andrei("        Andrei");
    std::thread andreiWork(andrei);

    Worker andrew("          Andrew");
    std::thread andrewWork(andrew);

    Worker david("            David");
    std::thread davidWork(david);

    herbWork.join();
    scottWork.join();
    bjarneWork.join();
    andreiWork.join();
    andrewWork.join();
    davidWork.join();

}
```
I have error.
workers.cpp:8:6: error: 'latch' in namespace 'std' does not name a type
    8 | std::latch workDone(6);
      |      ^~~~~
When I use 'latch.h' gcc 11.3.0 and above hasn't problem.
https://github.com/luncliff/latch/blob/master/latch.h
I have not error.=