What is escape in golang

Golang is a development language known for its efficiency, security and programmer-friendliness. In the Golang compilation process, escape is a very important concept. Escapes can affect program performance and may cause memory leaks. This article will introduce what escapes in Golang are, why they are important, and discuss how to avoid escapes.

1. What is escape?

Escape analysis refers to determining whether a variable will be allocated on the stack or the heap during the function life cycle.

Stack and heap are two ways of memory management in Golang. The stack is used to store function variables and function call context. These variables are automatically released at the end of the function call. The heap is memory that is manually allocated and released by the programmer. The variables in the heap exist until the end of the program.

If a variable is allocated on the heap during the function's lifetime, it is called an escape. This usually means that the variable's lifetime exceeds the function's lifetime.

Escape occurs in the following situations:

1. Assign a variable to a pointer defined outside a function.
2. Assign a variable to a global variable.
3. Assign a variable to the return value of an escape function.
4. Pass a variable to an escape function, and the escape function passes it to another function.

In these cases, the compiler allocates the variable on the heap rather than the stack to ensure that the variable still exists after the function call ends.

2. The Importance of Escape

Understanding the concept of escape is crucial for Golang programming. If the variables used escape, the following problems may exist:

1. Memory footprint: The escaped variables will be located in the program's heap, which will increase the program's memory footprint. Allocation and deallocation operations on the heap are generally much more expensive than operations occurring on the stack.
2. Performance: Accessing variables on the heap is generally slower than accessing variables on the stack. Therefore, performance degradation may occur when using escape variables.
3. Memory leak: The life cycle of the escape variable exceeds the life cycle of the function. If they are not handled correctly, they can take up too much memory during program execution, causing the program to crash or become slow.

3. How to avoid escape?

Avoiding escapes usually requires optimization and adjustment of the program. Here are some techniques and strategies that can be used:

1. Reduce the reference type returned by a function

If a function returns a reference type (pointer, slice, map, channel, etc. ), escape is likely to occur. To avoid this problem, you should minimize the number of reference types returned by functions. Consider using these types as function parameters rather than return values.

2. Avoid allocating in a loop

Allocating memory in a loop is one of the main causes of escapes. Variables can be declared outside the loop and reused within the loop.

3. Use literals

Using literals can reduce allocations and escapes on the heap. For example, using "[3]int{}" instead of "new([3]int)" can avoid escaping.

4. Use sync.Pool

You can use sync.Pool to reduce memory allocation and escape. sync.Pool is an efficient object pool that caches allocated objects and reuses them.

5. Use cache

Cache can avoid escapes and memory allocation. Caching can be implemented using data structures such as Golang's "sync.Map" and "Container/list".

4. Summary

Escape is an important concept in Golang programming. Understanding escapes can help programmers better optimize and manage memory. Avoiding escapes requires strategies that consider memory allocation and object reuse when writing code. By reducing function return reference types, avoiding allocation in loops, using literals, using sync.Pool and caching, etc., you can reduce escape and memory leak problems and improve program performance and stability.

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