g++ 编译returning reference to local temporary object 但是运行依然得到预期结果？

代码来自 C++ templates 第二版:

#include <cstring> #include <iostream> using std::cout; using std::endl; // maximum of two values of any type (call-by-reference) template <typename T> T const &max(T const &a, T const &b) { cout << "T const &max(T const &a, T const &b) called" << endl; return b < a ? a : b; } // maximum of two C-strings (call-by-value) char const *max(char const *a, char const *b) { cout << "char const *max(char const *a, char const *b) called" << endl; cout << a << endl; cout << b << endl; return std::strcmp(b, a) < 0 ? a : b; } // maximum of three values of any type (call-by-reference) template <typename T> T const &max(T const &a, T const &b, T const &c) { return max(max(a, b), c); // error if max(a,b) uses call-by-value } int main() { char const *s1 = "frederic"; char const *s2 = "anica"; char const *s3 = "lucas"; auto m2 = ::max(s1, s2, s3); // run-time ERROR //!!! m2 已经是一个 dangling reference ，但是仍然得到预期结果？ cout << m2 << endl; } 

不理解的地方在最后一行，m2 已经是一个 dangling reference ，但是为什么输出仍然得到预期结果？

编译使用的是 g++：

$ g++ --version 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 12.0.0 (clang-1200.0.31.1) Target: x86_64-apple-darwin21.1.0 Thread model: posix InstalledDir: /Library/Developer/CommandLineTools/usr/bin 

编译输出：

$ g++ test2.cpp -o test2 -std=c++11 test2.cpp:28:12: warning: returning reference to local temporary object [-Wreturn-stack-address] return max(max(a, b), c); // error if max(a,b) uses call-by-value ^~~~~~~~~~~~~~~~~ test2.cpp:36:17: note: in instantiation of function template specialization 'max<const char *>' requested here auto m2 = ::max(s1, s2, s3); // run-time ERROR ^ 1 warning generated. 

运行结果：

char const *max(char const *a, char const *b) called frederic anica char const *max(char const *a, char const *b) called frederic lucas lucas