char buf[1024]; memset(buf, 0, sizeof(buf)); memcpy(buf, &msg, sizeof(msg)); 什么意思

src, strlen(src));

This code initializes a character array called buf with a size of 1024 and sets all its elements to 0 using memset. Then, it copies the content of a string called src into buf using memcpy. The length of src is obtained using strlen, which returns the number of characters in the string excluding the null terminator. The content of src is copied into buf starting from the first element of buf. If the length of src is greater than the size of buf, memcpy will copy only up to the size of buf.