Implementation:ClickHouse ClickHouse Scope Guard

Knowledge Sources	ClickHouse
Domains	Resource_Management, Patterns
Last Updated	2026-02-08 00:00 GMT

Overview

RAII-based scope guard for automatic cleanup actions when leaving a scope.

Description

Executes a function on destruction, providing exception-safe cleanup. Supports move semantics, joining multiple guards, and manual reset.

Usage

Use for ensuring cleanup code runs (closing files, unlocking mutexes, rolling back transactions), especially in exception paths.

Code Reference

Source Location

• Repository: ClickHouse
• File: base/base/scope_guard.h
• Lines: 1-116

Signature

template <class F>
class BasicScopeGuard {
public:
    constexpr BasicScopeGuard(F && function_);
    ~BasicScopeGuard();
    void reset();
    F release();
};

using scope_guard = BasicScopeGuard<std::function<void(void)>>;

template <class F>
inline BasicScopeGuard<F> make_scope_guard(F && function_);

#define SCOPE_EXIT(...) /* ... */

Import

#include <base/scope_guard.h>

Usage Examples

#include <base/scope_guard.h>

void process() {
    FILE* f = fopen("file.txt", "r");
    SCOPE_EXIT({ if (f) fclose(f); });
    
    // File guaranteed to close on any exit path
}

// Manual scope guard
auto guard = make_scope_guard([&]() {
    cleanup_resources();
});

// Release guard if cleanup not needed
if (success)
    guard.release();

Related Pages

• Principle:ClickHouse_ClickHouse_RAII_Scope_Guard