pad.c

#include <stdio.h>

typedef struct {
    char her;
    long double hear[16];
    int hero;
    float yo[17];
} A;

#pragma pack(1)

typedef struct Apack {
    char her;
    long double hear[16];
    int hero;
    float yo[17];
} Apack;

int main() {
  {
    A s;
    printf("%zu = char: %zu, ldouble[16]: %zu, int: %zu, float[17]: %zu\n"
          , sizeof(s), sizeof(s.her), sizeof(s.hear)
          , sizeof(s.hero), sizeof(s.yo));
  }
  {
    Apack s;
    printf("%zu = char: %zu, ldouble[16]: %zu, int: %zu, float[17]: %zu\n"
          , sizeof(s), sizeof(s.her), sizeof(s.hear)
          , sizeof(s.hero), sizeof(s.yo));
  }
#pragma options align=reset
  {
    A s[7];
    printf("%zu\n", sizeof(s));
  }
    Apack s[7];
    printf("%zu\n", sizeof(s));
}