The difference between new () and make () in the Go language

This is a creation in Article, where the information may have evolved or changed.

http://se77en.cc/2014/04/25/the-difference-between-function-new-and-make-in-golang/

Overview

The Go language new and make has always been the novice more easily confused things, I look very similar. But explaining the difference between the two is also very easy.

Key features of new

The first new is the built-in function, you can see it from http://golang.org/pkg/builtin/#new here, and its definition is simple:

1	New (type) *type

The official documentation describes it as:

The built-in function new is used to allocate memory, its first parameter is a type, not a value, and its return value is a pointer to the new assigned type 0 value

Based on this description, we can implement a similar new function ourselves:

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func newint () *int { varint return &i}someint: = Newint ()

Our function is identical to the function someInt := new(int) . So when we define our own functions that start with new, we should also return pointers to types for conventions.

Key features of Make

makeis also a built-in function, you can see it from http://golang.org/pkg/builtin/#make here, its definition is new more than one parameter, the return value is also different:

1	Func make (typetype

The official documentation describes it as:

The built-in function is make used to slice map allocate memory for, or type, chan and initialize an object ( Note : Only available on these three types), new like, the first parameter is also a type instead of a value, new unlike the makereturns a reference to a type other than a pointer, and the return value depends on the type that is passed in, as described below:

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The size specifies its length, and its capacity and length are the same. You can pass in the third parameter to specify a different capacity value, but must not be smaller than the length value. such as make ([]int0size0size0 or ignore capacity, pipeline is no buffer

Summarize

newThe function of initializing a pointer to a type ( *T ) make is to initialize slice map chan and return a reference ( T ).