Why can't C compilers rearrange struct members to eliminate alignment padding? [duplicate]

Answer 1

C [and C++] are regarded as systems programming languages so they provide low level access to the hardware, e.g., memory by means of pointers. Programmer can access a data chunk and cast it to a structure and access various members [easily].

Another example is a struct like the one below, which stores variable sized data.

struct {
  uint32_t data_size;
  uint8_t  data[1]; // this has to be the last member
} _vv_a;