Have you used context? What are the use cases for context?
Answer
| Scenario | Introduction |
|---|---|
| Timeout handling | By using context, you can easily set a timeout, and the coroutine will automatically terminate after the timeout |
| Terminate coroutine | By using the cancel() method, coroutines can be easily terminated |
| Data transfer | We can write data into context to transfer data between different coroutines |
Is channel thread-safe?
Answer
channel is thread-safe, the reason is that channel has implemented a lock mechanism internally,
Map
Is the traversal of a Map using range ordered or unordered?
Answer
Unordered
Internally, Map uses a hash algorithm to place elements. When it automatically expands, it recalculates the hash values, so the addresses of the elements keep changing. To prevent users from thinking that the arrangement of Map elements is ordered, it directly returns in a random order, so the traversal is unordered.
Is Map concurrency-safe?
Answer
Map cannot guarantee concurrency safety
To ensure concurrency safety, use the following methods:
- Manually add read-write locks
- Use
sync.Map
Will the memory of a key be released after the key is deleted from the Map?
Answer
If the value of the map is
- Value type (
intuintfloat32stringstruct{}...), then the value will not be garbage collected after the key is deleted - Reference type (
mapsliceschan...), then the value will be garbage collected after the key is deleted
If we want to force garbage collection, how do we operate?
- Set the map to nil
- Place the values that need to be retained in a new map and assign it to the current map
Exclusive for members
Can a panic caused by a map be recovered?
Answer
A panic caused by concurrent read and write operations on a map cannot be recovered. This is because map-related panics are thrown using runtime.throw(), which cannot be recovered.
if h.flags&hashWriting != 0 {
throw("concurrent map read and map write")
}