How to add stack traces to assertion failures?

[Seb-C]

Hello,

I've been using this library for a while, and it's been super useful to me so far, thanks for making it!

Apologizes if there is an easy way that I overlooked (I'm quite new to C++), but I have been trying for a while to intercept and get a proper stack trace for runtime assertion failures, without success.

Is there any way to do this currently in cpptrace (or maybe a hint as to how I could achieve this)?

Exception handling does not catch it (as expected). It does not seem possible to intercept it with a terminate_handler either, and intercepting SIGABRT didn't help.

Example:

#include <cpptrace/cpptrace.hpp>
#include <iostream>
#include <memory>

struct Foo {
	int x;
};

int triggerAssertFailure() {
	auto foo = std::make_unique<Foo>(42);
	auto bar = std::move(foo);
	Foo& fooPtr = *foo; // <- Making it fail here
	return fooPtr.x;
}

int main() {
	cpptrace::absorb_trace_exceptions(false);
	cpptrace::use_default_stderr_logger();
	cpptrace::register_terminate_handler();

	std::cout << "RESULT: " << triggerAssertFailure() << "\n";

	std::cout << "DONE\n";
	return 0;
}

/usr/lib/gcc/x86_64-linux-gnu/15/../../../../include/c++/15/bits/unique_ptr.h:455: typename add_lvalue_reference<element_type>::type std::unique_ptr<Foo>::operator*() const [_Tp = Foo, _Dp = std::default_delete<Foo>]: Assertion 'get() != pointer()' failed.

[Seb-C]

I was able to hack something, but it's not ideal, hopefully there is a cleaner way 🤔

#include <bits/c++config.h>
#undef __glibcxx_assert
#define __glibcxx_assert(condition) \
	do { \
		if (!(condition)) { \
			throw "Failed assertion"; \
		} \
	} while(false)

#include <cassert>
#undef assert
#define assert(condition) \
	do { /* NOLINT */ \
		if (!(condition)) { \
			throw "Failed assertion"; \
		} \
	} while(false)

[jeremy-rifkin]

Hi,
Glad the library has been useful!

There are a few ways you could try to add stack traces to assertion failures:

1. Use your own assert macro definition where you print a stack trace in the failure handler
   • Perhaps libassert is of interest
2. By default assert will call abort() which raises SIGABRT, you could add a handler for this signal that prints a stack trace (ideally using the signal-safe tracing mechanism)
3. I think it should be possible to hook glibc's __assert_fail, which is called on assert failure, with your own implementation

I highly recommend the first option if the assertions are in code you control (or the assertions are in headers you're #including, like <memory>).

Happy to help if you run into any other issues!

[Seb-C]

Thanks!

I'm looking to get a stack for assertions in third-party libraries or the standard one, so I think that the option 1 might not be reliable or consistent enough in my case.

I already tried option 2 and SIGABRT was never triggered either, so I guess that I'll have to look at option 3, or keep my current hack.