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#include <assert.h>
#define CONCAT(a, b) a##b
#define CONCAT2(a, b) CONCAT(a, b)
#define STATIC_ASSERT(condition) \
int CONCAT2(some_array, __LINE__)[(condition) ? 1 : -1]
struct my_struct1
{
int i;
char ch;
struct
{
// this gets padded
int j;
};
// Bit-fields do not get padded in between,
// but fill up an integer!
unsigned bf1:1;
unsigned bf2:28;
} xx1 =
{
1, 2, { .j=3 }
};
struct my_struct2
{
int i;
char ch[4];
// no padding needed
int j;
char ch2;
// there may be end-padding!
} xx2;
struct my_struct3 {
unsigned int bit_field : 1;
int i;
} xx3= { 1, 2 };
STATIC_ASSERT(sizeof(xx1)==4+1+3+4+4);
STATIC_ASSERT(sizeof(xx2)==4+4+4+4);
int main()
{
assert(xx1.i==1);
assert(xx1.ch==2);
assert(xx1.j==3);
// let's probe the padding
char *p=&xx1.ch;
assert(p[0]==2);
assert(p[1]==0);
assert(p[2]==0);
assert(p[3]==0);
assert(xx3.bit_field==1);
assert(xx3.i==2);
}
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