标签:种类 buffered 内置函数 aci not ror like 并且 必须
new 和 make 是两个内置函数,主要用来创建并分配类型的内存。在我们定义变量的时候,可能会觉得有点迷惑,不知道应该使用哪个函数来声明变量,其实他们的规则很简单,
new 只分配内存,
make 只能用于 slice、map 和 channel 的初始化,
下面我们就来具体介绍一下:
在Go语言中,new 函数描述如下:
// The new built-in function allocates memory. The first argument is a type, // not a value, and the value returned is a pointer to a newly // allocated zero value of that type. func new(Type) *Type
var sum *int sum = new(int) //分配空间 *sum = 98 fmt.Println(*sum)
type Student struct { name string age int } var s *Student s = new(Student) //分配空间 s.name ="dequan" fmt.Println(s)
panic: runtime error: invalid memory address or nil pointer dereference [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x80bd277] goroutine 1 [running]:
// The make built-in function allocates and initializes an object of type // slice, map, or chan (only). Like new, the first argument is a type, not a // value. Unlike new, make‘s return type is the same as the type of its // argument, not a pointer to it. The specification of the result depends on // the type: // Slice: The size specifies the length. The capacity of the slice is // equal to its length. A second integer argument may be provided to // specify a different capacity; it must be no smaller than the // length, so make([]int, 0, 10) allocates a slice of length 0 and // capacity 10. // Map: An empty map is allocated with enough space to hold the // specified number of elements. The size may be omitted, in which case // a small starting size is allocated. // Channel: The channel‘s buffer is initialized with the specified // buffer capacity. If zero, or the size is omitted, the channel is // unbuffered. func make(t Type, size ...IntegerType) Type
注意:make 函数只用于 map,slice 和 channel,并且不返回指针。如果想要获得一个显式的指针,可以使用 new 函数进行分配,或者显式地使用一个变量的地址。
Go语言中的 new 和 make 主要区别如下:标签:种类 buffered 内置函数 aci not ror like 并且 必须
原文地址:https://www.cnblogs.com/lurenq/p/12013250.html