GO Goroutines and Concurrency 3

Question 1

What is a goroutine leak?

Accepted Answer

A goroutine that never terminates and is never garbage collected

Answer

A goroutine that uses too much memory

Answer

A goroutine that panics silently

Answer

A goroutine blocked on I/O

Question 2

What is the zero value of a `sync.Mutex`?

Accepted Answer

unlocked and ready to use

Answer

nil

Answer

locked state

Answer

undefined

Question 3

Which context function creates a context that can be cancelled manually?

Accepted Answer

context.WithCancel()

Answer

context.Background()

Answer

context.WithTimeout()

Answer

context.TODO()

Question 4

What happens if you call `cancel()` returned by `context.WithCancel` multiple times?

Accepted Answer

Only the first call has effect; subsequent calls are no-ops

Answer

It panics

Answer

It cancels child contexts again

Answer

It resets the context

Question 5

Which atomic operation in `sync/atomic` swaps a value only if it matches an expected value?

Accepted Answer

atomic.CompareAndSwapInt64

Answer

atomic.AddInt64

Answer

atomic.StoreInt64

Answer

atomic.LoadInt64

Question 6

What does the `select` statement do when multiple channels are ready simultaneously?

Accepted Answer

Picks a ready case pseudo-randomly

Answer

Executes all ready cases

Answer

Panics with ambiguous select

Answer

Executes the first case in order