为什么包括原子-给出错误

Why including atomic - gives errors

本文关键字：出错 错误 包括原 为什么      更新时间：2023-10-16

我在ubuntu 64位14.04下使用g++ (gcc) 4.9.2版本。我正在尝试编译以下简单的代码:

#include <iostream>
#include <atomic>
using namespace std;
int main() {
    cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
    return 0;
}

得到以下错误:

/usr/include/c++/4.9/atomic:385:56: error: ‘noexcept’ does not name a type
      memory_order __m = memory_order_seq_cst) volatile noexcept
                                                        ^
/usr/include/c++/4.9/atomic:389:53: error: expected ‘;’ at end of member declaration
       load(memory_order __m = memory_order_seq_cst) const noexcept
                                                     ^
/usr/include/c++/4.9/atomic:389:59: error: ‘noexcept’ does not name a type
       load(memory_order __m = memory_order_seq_cst) const noexcept
                                                           ^
/usr/include/c++/4.9/atomic:393:59: error: expected ‘;’ at end of member declaration
       load(memory_order __m = memory_order_seq_cst) const volatile noexcept
                                                           ^
/usr/include/c++/4.9/atomic:393:68: error: ‘noexcept’ does not name a type
       load(memory_order __m = memory_order_seq_cst) const volatile noexcept
                                                                    ^
/usr/include/c++/4.9/atomic:398:48: error: expected ‘;’ at end of member declaration
         memory_order __m = memory_order_seq_cst) noexcept
                                                ^
/usr/include/c++/4.9/atomic:398:50: error: ‘noexcept’ does not name a type
         memory_order __m = memory_order_seq_cst) noexcept

为什么我不能编译这个简单的例子?

查看第一个错误，而不是最后一个。后面的错误通常是由前面的错误引起的，所以只看最后的错误是浪费时间，而且不能告诉你根本原因。

第一个错误将是:

从/usr/include/c++/4.9/atomic:38:0从a.cc: 2:/usr/include/c++/4.9/bits/c++0x_warning.h:32:2: error: #error此文件需要编译器和库支持ISO c++ 2011标准。此支持目前是实验性的，必须通过-std=c++11或-std=gnu++11编译器选项启用。

这应该是完全明显的。你没有告诉编译器你想使用c++ 11

它甚至告诉你如何解决问题:用-std=c++11或-std=gnu++11编译

注意:对于GCC 5的<atomic>头被修改，所以你只有得到一个错误，而不是所有的结果落在它之后。

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