Structure s_color4 members alignment problem

[vinz6751]

"types.h" defines the following structure to represent a 32 bit color:

typedef struct s_color4 {
    uint8_t blue;
    uint8_t green;
    uint8_t red;
    uint8_t alpha;
} t_color4;

I suspect that VBCC will align structure members on word or long word boundaries. So if you want to align the members on bytes instead (so the whole structure is 4 bytes), you should wrap the declaration with:

#pragma pack(1)
typedef struct s_color4 {
...
} t_color4;
#pragma pack()

as indicated on page 46 of the VBCC manual.
I haven't tested it though

It struck me because for the EmuTOS port I had the problem and had to use the packed attribute to indicate what I wanted to GCC.

[pweingar]

Thanks. I don't think this record ended up being used... it might be a hold over from when I started working on the code on my C256. It should probably be removed.

[vinz6751]

I saw it was not used, but I thought it was because it was not working :D
Sometimes it's just easier to use a unsigned long.
So a colour could really be defined as a union, e.g:

union color {
  unsigned long l; // Requires the user to know the order of components but makes for easier conversion long <-> union
  t_color4 argb;
}

Anyway, as you way it can probably be deleted until we need it.