defer.hpp
Go’s defer implementation in C++17
Requirements
Installation
defer.hpp is a header-only library. All you need to do is copy the headers files from headers directory into your project and include them:
#include "defer.hpp/defer.hpp"
Also, you can add the root repository directory to your cmake project:
add_subdirectory(external/defer.hpp)
target_link_libraries(your_project_target PUBLIC defer.hpp::defer.hpp)
Examples
Basic Defer
if ( FILE *file = std::fopen("output.txt", "a") ) {
// defer will close the file after scope or on exception
DEFER_HPP([file]{ std::fclose(file); });
const char buffer[] = "hello world\n";
if ( 12 != std::fwrite(buffer, sizeof(buffer[0]), std::strlen(buffer), file) ) {
throw std::runtime_error("some exception");
}
}
Error Defer
if ( FILE *file = std::fopen("output.txt", "a") ) {
// defer will close the file after scope or on exception
DEFER_HPP([file]{ std::fclose(file); });
// error defer will be called on exception
ERROR_DEFER_HPP([]{
std::cerr << "there is something wrong" << std::endl;
});
const char buffer[] = "hello world\n";
if ( 12 != std::fwrite(buffer, sizeof(buffer[0]), std::strlen(buffer), file) ) {
throw std::runtime_error("some exception");
}
}
Return Defer
if ( FILE *file = std::fopen("output.txt", "a") ) {
// defer will close the file after scope or on exception
DEFER_HPP([file]{ std::fclose(file); });
// return defer will be called on successful scope exit
RETURN_DEFER_HPP([]{
std::cout << "all is ok!" << std::endl;
});
const char buffer[] = "hello world\n";
if ( 12 != std::fwrite(buffer, sizeof(buffer[0]), std::strlen(buffer), file) ) {
throw std::runtime_error("some exception");
}
}