Crafter.Build/tests/WasmExceptions/fixture/main.cpp

// SPDX-License-Identifier: LGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

import std;

// jump.c, compiled as C.
extern "C" std::int32_t JumpRoundTrip();

namespace {
    std::int32_t unwound = 0;

    struct Guard {
        ~Guard() { ++unwound; }
    };

    void Throw(std::int32_t depth) {
        Guard guard;
        if (depth == 0) throw std::runtime_error("thrown in wasm");
        Throw(depth - 1);
    }
}

int main(int argc, char** argv) {
    // With an argument, nothing catches: the run has to fail.
    if (argc > 1) Throw(0);
    try {
        Throw(3);
    } catch (const std::runtime_error& e) {
        std::println("caught: {} after {} destructors", e.what(), unwound);
    }
    try {
        const std::vector<std::int32_t> empty;
        std::println("unreachable: {}", empty.at(1));
    } catch (const std::out_of_range&) {
        std::println("caught: out_of_range from libc++");
    }
    // vector::at throws from a header, compiled into this unit; stoi throws
    // inside libc++.a, which therefore has to be the exception-enabled one.
    try {
        std::println("unreachable: {}", std::stoi("not a number"));
    } catch (const std::invalid_argument&) {
        std::println("caught: invalid_argument from inside libc++");
    }
    std::println("longjmp came back with {}", JumpRoundTrip());
    return 0;
}