golang new failed

When using Golang, if you use the new statement to create a pointer type variable, there may be a problem of new failure. In this case, the program will throw a runtime exception when running, causing the program to fail to run normally. This article will analyze the reasons why new fails in Golang and provide solutions.

1. Usage of new statement in Golang

The new statement in Golang is used to create a new variable of a specified type and return the address of this variable. The syntax format of the new statement is as follows:

new(T)

Among them, T is the type of the variable. The new statement will create a new variable pointing to this type and return its address. The code example is as follows:

var p *int
p = new(int)

In the above code, the new(int) statement creates a new int type variable and saves its address in the p pointer variable.

2. Analysis of the reasons for new failure

Normally, the new statement in Golang will not fail. But in some special cases, the new statement may fail and return a nil value. The following are possible reasons for the failure of new:

(1) Insufficient memory

When the memory allocator cannot allocate the required memory for the variable, the new statement will fail and return a nil value. This situation generally occurs when there is insufficient memory when the program is running.

(2) Pointer type error

When the new statement attempts to create a variable that does not support a pointer type, the new statement will fail and return a nil value.

(3) Program concurrency issues

When program concurrency issues cause multiple coroutines to call the new statement at the same time, the new statement may fail and return a nil value. This situation generally occurs in multi-threaded programs.

3. Methods to solve new failure

In Golang, there are the following methods to solve new failure:

(1) Check whether the system memory is Enough

When the new statement returns a nil value, you can use system tools to view the system's memory usage to determine whether there is an insufficient memory problem. If there is indeed a problem of insufficient memory, you need to optimize the program to reduce memory usage.

(2) Avoid using new statements in multiple coroutines at the same time

To avoid problems with new statements during concurrency, you can use concurrency control methods such as locks to ensure the thread safety of new statements. .

(3) Use the make statement instead of the new statement

Using the make statement can specify the length and capacity of the variable while creating it, thereby avoiding the problem of the new statement failing due to insufficient memory and other reasons.

(4) Consider using sync.Pool

When using the new statement multiple times to create the same type of variables, you can consider using sync.Pool to cache the variables created by the pool to avoid frequent Call the new statement.

For example, you can use the following code to create a cache pool:

var pool = &sync.Pool{
    New: func() interface{} {
        return new(int)
    },
}

The above code creates a variable cache pool of type int. When in use, you can obtain the address of an int type variable by calling the pool.Get() method (returns if there is an available variable in the cache pool, otherwise creates a new variable). After using the variable, put the variable back into the cache pool by calling the pool.Put() method so that it can be reused in subsequent operations.

4. Summary

In Golang, the new statement generally does not fail. But in some special cases, the new statement may fail, causing the program to fail to run normally. We should understand the reason why the new statement failed and take corresponding solutions according to the specific situation to ensure that the program can run stably and reliably.

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