examples/basic-usage/src/main.cpp

#include <iostream>
 
#include "errors/errors.hpp"
 
using errors::error_ptr;
using errors::impl::runtime_error;
 
// NOTE:
// If you have a function which might goes wrong,
// but you don't want to or can not to throw an exception,
// you can return an error_ptr.
error_ptr fn() noexcept
{
        return errors::make<runtime_error>::with("error occurs");
};
 
// NOTE:
// You can return an wrapped error_ptr using the `wrap` function.
error_ptr fn2() noexcept
{
        auto err = fn();
        return errors::wrap(fn());
}
 
int main()
{
        auto err = fn2();
 
        // NOTE:
        // This will print something like:
        // ```
        // Error: error occurs
        // ```
        // The wrap() call in fn2 with no message will be omitted
        // in default error printer function.
        std::cerr << "Error: " << err << std::endl;
 
        // NOTE:
        // But the wrapped error does record the wrap() source_location to err.
        // You can get it by calling err->location()
        auto loc = err->location();
        assert(loc.has_value());
        std::cerr << "Error function: " << loc->function_name() << std::endl
                  << "Error file_name: " << loc->file_name() << std::endl
                  << "Error line: " << loc->line() << std::endl
                  << "Error column: " << loc->column() << std::endl;
 
        // NOTE:
        // Or use json output.
#if defined(ERRORS_ENABLE_NLOHMANN_JSON_SUPPORT)
        std::cerr << "Error in JSON:" << std::endl
                  << nlohmann::json(err) << std::endl;
#endif
 
        return 0;
}