Is the following code

#include <stdexcept>

int main() {
    throw std::runtime_error("foobar");
}

guaranteed to produce the following outout?

terminate called after throwing an instance of 'std::runtime_error'
  what():  foobar
fish: Job 1, './a.out' terminated by signal SIGABRT (Abort)

Can I rely on this exact output on every compiler? Can I rely on that what method will be called and error message will be printed will be printed?

CodePudding user response：

No it is not guaranteed, it unspecified whether there is any message. From cppreference:

If an exception is thrown and not caught, including exceptions that escape the initial function of std::thread, the main function, and the constructor or destructor of any static or thread-local objects, then std::terminate is called. It is implementation-defined whether any stack unwinding takes place for uncaught exceptions.

The case that is relevant here is "exceptions that escape [...] the main function". The call to std::terminate is guaranteed though. And you can install a std::terminate_handler to print a custom message if you like.