franta-hg@2: /**
franta-hg@2:  * cpp-finally
franta-hg@2:  * Copyright © 2024 František Kučera (Frantovo.cz, GlobalCode.info)
franta-hg@2:  *
franta-hg@2:  * This program is free software: you can redistribute it and/or modify
franta-hg@2:  * it under the terms of the GNU General Public License as published by
franta-hg@2:  * the Free Software Foundation, version 3 of the License.
franta-hg@2:  *
franta-hg@2:  * This program is distributed in the hope that it will be useful,
franta-hg@2:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
franta-hg@2:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
franta-hg@2:  * GNU General Public License for more details.
franta-hg@2:  *
franta-hg@2:  * You should have received a copy of the GNU General Public License
franta-hg@2:  * along with this program. If not, see <http://www.gnu.org/licenses/>.
franta-hg@2:  */
franta-hg@2: 
franta-hg@2: #include <iostream>
franta-hg@2: #include <exception>
franta-hg@2: #include <functional>
franta-hg@2: 
franta-hg@2: class Finally {
franta-hg@2: private:
franta-hg@2: 	Finally(const Finally&) = delete;
franta-hg@2: 	Finally& operator=(const Finally&) = delete;
franta-hg@2: public:
franta-hg@2: 	std::function<void(void) > fx;
franta-hg@2: 
franta-hg@2: 	Finally(std::function<void(void) > fx) : fx(fx) {
franta-hg@2: 	}
franta-hg@2: 
franta-hg@2: 	virtual ~Finally() {
franta-hg@2: 		fx();
franta-hg@2: 	}
franta-hg@2: };
franta-hg@2: 
franta-hg@2: void fxThrowing(bool fail, void* data) {
franta-hg@2: 	std::cout << "  doing something with data " << data << std::endl;
franta-hg@2: 	if (fail) throw std::logic_error("error from fxThrowing()");
franta-hg@2: }
franta-hg@2: 
franta-hg@2: void fxAllocating(bool fail) {
franta-hg@2: 	void* buf = malloc(486);
franta-hg@2: 	void* tmp = malloc(123);
franta-hg@2: 	std::cout << "  allocated memory at: " << buf << std::endl;
franta-hg@2: 	std::cout << "  allocated memory at: " << tmp << std::endl;
franta-hg@2: 
franta-hg@2: 	Finally finally([&]() {
franta-hg@2: 		free(buf);
franta-hg@2: 		free(tmp);
franta-hg@2: 		std::cout << "  freed memory at: " << buf << std::endl;
franta-hg@2: 		std::cout << "  freed memory at: " << tmp << std::endl;
franta-hg@2: 	});
franta-hg@2: 
franta-hg@2: 	fxThrowing(fail, buf);
franta-hg@2: 	fxThrowing(fail, tmp);
franta-hg@2: }
franta-hg@2: 
franta-hg@2: int main(int argc, char** argv) {
franta-hg@2: 	bool fail = argc == 2 && std::string("fail") == argv[1];
franta-hg@2: 	const char* name = "good-lambda";
franta-hg@2: 	std::cout << name << " (fail=" << fail << ")\n";
franta-hg@2: 	try {
franta-hg@2: 		fxAllocating(fail);
franta-hg@2: 	} catch (const std::exception& e) {
franta-hg@2: 		std::cout << "  caught exception: " << e.what() << std::endl;
franta-hg@2: 	}
franta-hg@2: }