MacOS 上的 c++11 警告

Question

我的 Mac 上有 clang 13.0.0。 我正在尝试使用命令编译一些.cpp文件

g++ file.cpp -o file

但我收到此警告消息：

file.cpp:23:26: warning: range-based for loop is a C++11 extension [-Wc++11-extensions]
    for (const double &e : timestamp) outFile << std::setprecision(10) << e << "\n";

On the clang documentation is said that c++11 is supported by clang 13. On my terminal running man clang I find: The default C++ language standard is gnu++14 .

输入g++ -v我得到：

Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 13.0.0 (clang-1300.0.29.3)
Target: arm64-apple-darwin21.1.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

为什么我会收到此警告？

Answer 1

AppleClang默认为c++98，而llvm-clang默认为后面的gnu++14； 要访问 c++11 实现，您必须添加标志--std=c++11或--std=c++14 。 参看。 https://opensource.apple.com/source/clang/clang-703.0.29/src/tools/clang/www/cxx_status.html

If you are expecting the gnu g++ , it must be installed separately, because on macOS g++ aliases to clang , which is the Apple fork of clang known as AppleClang .

如果您期待llvm-clang ，那也必须单独安装。 AppleClang 13 ≠ llvm-clang 13。