Disable structure padding in C without using pragma

Question

How can I disable structure padding in C without using pragma?

Answer 1

Other than compiler options like pragma pack, you cannot, padding is in the C Standard.

You can always attempt to reduce padding by declaring the smallest types last in the structure as in:

struct _foo {
     int a;  /* No padding between a & b */
     short b;
} foo;

struct _bar {
     short b; /* 2 bytes of padding between a & b */
     int a;
} bar;

Note for implementations which have 4 byte boundaries