Struct packing and alignment with mingw

Question

I am emulating code from an embedded system (stm32, Keil µVision 5, MDK-ARM) on a PC (mingw32, 32bit arch). The alignment of the ARM compiler does not match my desktop m

Answer 1

According to the GCC manual's examples, the attribute should go after the struct's fields, i.e.:

// PC Code
typedef struct
{
    uint8_t var1;
    uint16_t var2;
} __attribute__((packed, aligned(1))) FILE;

I also dropped the pointless struct tag (_file).

The above has a sizeof value of 3 when I tested it quickly.