# interrupt() Interrupts long-running validation operations — reindex, block import, `ChainstateManager.processBlock`. ``` func interrupt() -> Bool ``` ## Return Value `true` if the kernel accepted the interrupt signal. `false` indicates the kernel rejected the request (typically because no interruptible operation was in flight). ## Discussion Safe to call from any thread. Signals the kernel to stop at the next safe checkpoint; interruption is cooperative — a call in flight completes the current step before unwinding. Used by [`BlockchainSync`](/documentation/BitcoinKernel/BlockchainSync) to stop sync on consumer cancel.