Defer in ObjC. See more at https://pspdfkit.com/blog/2017/even-swiftier-objective-c

PSPDFDefer.m

// Similar to defer in Swift
#define pspdf_defer_block_name_with_prefix(prefix, suffix) prefix ## suffix
#define pspdf_defer_block_name(suffix) pspdf_defer_block_name_with_prefix(pspdf_defer_, suffix)
#define pspdf_defer __strong void(^pspdf_defer_block_name(__LINE__))(void) __attribute__((cleanup(pspdf_defer_cleanup_block), unused)) = ^
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-function"
static void pspdf_defer_cleanup_block(__strong void(^*block)(void)) {
    (*block)();
}
#pragma clang diagnostic pop