Golang接口所需的空间

How much space (in bytes) does a Golang interface take up?

For example, which would take up more space?

type Stringer interface { String() string }

strSlice := make([]string, 4)
stringerSlice := make([]Stringer, 4)

• interface consumes 2 words of memory: 1 word for runtime type and 1 word for data pointer;
• string consumes 2 words of memory: 1 word for base pointer and 1 word for length;
• slice consumes 3 words of memory: 1 word for base pointer, 1 word for length and 1 word for capacity;
• function, channel and map consume 1 word.

Based on the machine type(32bit or 64bit) word size is 4 bytes length or 8 bytes length respectively.

Interace is a structure of 2 words:

• pointer to data
• pointer to itab - table of methods.

So at 64-bit machine: it will take 8*2=16 bytes.