How to solve the "invalid address memory or nil pointer dereference" error in golang?

In Golang, "invalid memory address or nil pointer dereference" is the most common error. This error often causes the program to crash, so it's important to determine why it went wrong and fix it. This article explains how to identify and resolve these errors.

1. What is "invalid memory address or nil pointer dereference" error?

This error usually occurs when an unallocated or uninitialized pointer is accessed. A pointer is a variable that stores a memory address. In Golang, if a pointer is not allocated or initialized, its value will be nil. If you try to access a nil pointer, an "invalid memory address or nil pointer dereference" error will occur.

The following is an example:

var ptr *int
*ptr = 3

In this example ptr is an unallocated pointer, when trying to use * When ptr is assigned a value of 3, the "invalid memory address or nil pointer dereference" error will be triggered.

2. How to avoid "invalid memory address or nil pointer dereference" error?

First, you need to make sure all pointers are allocated and initialized. For example:

a := new(int)
*b = 10

Here, a is an allocated and initialized pointer, which will not appear when *a is assigned to it. mistake.

However, if you do not perform initialization and allocation operations, then an error will be triggered when *a is assigned.

var b *int
*b = 10

Here b is an unallocated and uninitialized pointer. When *b is assigned to it, "invalid memory address or nil pointer" will appear. dereference" error.

Therefore, when writing code, the allocation and initialization of pointers need to be handled carefully.

3. How to solve the "invalid memory address or nil pointer dereference" error?

When an "invalid memory address or nil pointer dereference" error occurs, you need to debug: first determine which pointer triggered the error. Once you have determined the corresponding pointer, you can check whether it has been allocated and initialized correctly.

If the pointer is not allocated and initialized as expected, it needs to be implemented manually in the program.

var variable int
a := &variable
// ...
*a = 10

Here, a is a pointer to variable, in *a Variable must be assigned before assignment.

Finally, you can use Golang’s built-in debugger to troubleshoot errors. The built-in debugger can print out the line number where the error occurred and stack trace information, helping to find and fix errors faster.

4. Summary

"invalid memory address or nil pointer dereference" error usually occurs when accessing an unallocated or uninitialized pointer, which can be solved by correctly allocating and initializing the pointer. Avoid; when an error occurs, you need to debug and find out the specific pointer, and manually complete its allocation and initialization in the program. Golang’s built-in debugger can also help locate errors.

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