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How do I create a buffered channel in Go? (e.g., make(chan int, 10))
To create a buffer channel in Go, just specify the capacity parameters in the make function. The buffer channel allows the sending operation to temporarily store data when there is no receiver, as long as the specified capacity is not exceeded, for example, ch := make(chan int, 10) creates a buffer channel that can store up to 10 integer values; unlike unbuffered channels, data will not be blocked immediately when sending, but the data will be temporarily stored in the buffer until it is taken away by the receiver; when using it, you need to pay attention to: 1. The capacity setting should be reasonable to avoid memory waste or frequent blocking; 2. The buffer needs to prevent memory problems from being accumulated indefinitely in the buffer; 3. The chan struct{} type can be used to pass signals to save resources; common scenarios include controlling the number of concurrent, producer-consumer models, asynchronous communication, etc.; In addition, attention should be paid to the correct time to close the channel to avoid repeated closing or forgetting to close the error.
Creating a buffered channel in Go is very simple, you just need to specify the second parameter in the make function. For example:
ch := make(chan int, 10)
This line of code creates a buffer channel that can store up to 10 integer values.
What is a buffer channel?
Normal unbuffered channels require that send and receive operations must occur simultaneously, otherwise they will block. The buffer channel allows you to send data first without the receiver, as long as the buffer is not full.
- Unbuffered channel:
make(chan int) - Buffered channel:
make(chan int, 10)
You can think of a buffer channel as a queue of finite capacity. The sent data will first enter this queue until it is taken away by the recipient.
Basic usage of buffer channels
After declaration, you can use it like using a normal channel:
ch := make(chan int, 3) ch <- 1 ch <- 2 ch <- 3 fmt.Println(<-ch) // Output 1 fmt.Println(<-ch) // Output 2 fmt.Println(<-ch) // Output 3
Here we create a buffer channel with a capacity of 3 and send three values ??in a row, without blocking, because there is still room.
Note: If you try to send data to a full buffer channel, the program will block until there is room.
Use scenarios and precautions
Common uses:
- Control the number of concurrency (such as limiting the maximum number of concurrencies of goroutine)
- Cache tasks in producer-consumer model
- Implement asynchronous communication or event queue
Common errors:
- Unclearing the buffering mechanism leads to deadlock
- Forgot to close the channel or repeatedly close it
- Unreasonable capacity setting, too large and waste memory, too small and frequent blockage
If you just want to pass signals instead of data, you can use chan struct{} type to save resources:
signal := make(chan struct{}, 1)Let's summarize
Creating a buffer channel is to add a capacity parameter when make . It is similar to unbuffered, but it is more flexible in behavior. It should be noted that the buffer accumulates data infinitely to avoid memory problems. Rational use of buffering can make your concurrent programs more efficient and controllable.
Basically that's it.
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