Linux 抛出主，即未捕获到SIGSEGV中的异常结果

发布于04月18日

#include <iostream>
#include <stdexcept>

class Test {
public:
    Test() { std::cout << "Constructor called" << std::endl; }
    ~Test() { std::cout << "Destructor called" << std::endl; }
};

int main() {
    Test obj1;

    try 
    {
        Test obj2;
        throw std::runtime_error("Exception thrown"); 
    } // Object 2 is destroyed here
    catch (...)
    {
        throw; // std::abort
    }
} // not reached (implementation defined), Object 1 destructor never called

我明白为什么不调用obj2的析构函数，因为如果在未捕获的异常的情况下发生堆栈展开，它就是定义的实现，但我不明白为什么在通常的Linux platforms it's allowed or thinks it has to terminate with a SIGSEGV signal上.据我了解，预计会出现SIGABRT.

推荐答案

这是一个人造品(/bug？)更轻松的探险家.SIGABRT变成SIGSEGV:https://github.com/compiler-explorer/compiler-explorer/issues/5224

在我的计算机上运行它会显示:

$ ./example ; echo "Program returned: $?"
Constructor called
Constructor called
Destructor called
terminate called after throwing an instance of 'std::runtime_error'
  what():  Exception thrown
Aborted
Program returned: 134

即使在Ensemer Explorer上，您也可以处理SIGABRT来查看它是否仍然存在，后面只有一个SIGSEGV:https://godbolt.org/z/6dYsP5K5K

std::signal(SIGABRT, [](int) {
    std::cout << "Caught SIGABRT\n" << std::flush;
});
std::signal(SIGSEGV, [](int) {
    std::cout << "Caught SIGSEGV\n" << std::flush;
    std::_Exit(1);
});

更简单的资源管理器输出:

Program returned: 1
terminate called after throwing an instance of 'std::runtime_error'
  what():  Exception thrown
Constructor called
Constructor called
Destructor called
Caught SIGABRT
Caught SIGSEGV

我的电脑:

$ ./example ; echo "Program returned: $?"
Constructor called
Constructor called
Destructor called
terminate called after throwing an instance of 'std::runtime_error'
  what():  Exception thrown
Caught SIGABRT
Aborted
Program returned: 134