#include <stdint.h>
#include <stdio.h>

typedef union
{
    uint8_t   uint8;
    int8_t    int8;
    uint16_t  uint16;
    int16_t   int16;
    uint32_t  uint32;
    int32_t   int32;
} my_union_t;

int main(void)
{
    my_union_t foo;

    foo.uint32 = 0x12345678;

    printf("uint8: %d, int8: %d, uint16: %d, int16: %d, uint32 %d, int32: %d\n",
           foo.uint8, foo.int8, foo.uint16, foo.int16, foo.uint32, foo.int32);


    return 0;
}

uint8: 120, int8: 120, uint16: 22136, int16: 22136, uint32 305419896, int32: 305419896