Padding in structures in C

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I don’t think there’s an advantage for any of this structures. There is one(!) constant in this equation. The order of the members of the struct is guaranteed to be as declared.

So in case like the following, the second structure might have an advantage, since it probably has a smaller size, but not in your example, as they will probably have the same size:

struct {
    char a;
    int b;
    char c;
} X;

Vs.

struct {
    char a;
    char b;
    int c;
} Y;

A little more explanation regarding comments below:

All the below is not a 100%, but the common way the structs will be constructed in 32 bits system where int is 32 bits:

Struct X:

|     |     |     |     |     |     |     |     |     |     |     |     |
 char  pad    pad   pad   ---------int---------- char   pad   pad   pad   = 12 bytes

struct Y:

|     |     |     |     |     |     |     |     |
 char  char  pad   pad   ---------int----------        = 8 bytes

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