[GRASS-dev] lib fn to convert int color number to RGB values?

[Moritz Lennert]

On 30/01/08 07:15, Ivan Shmakov wrote:
>>>>>> Glynn Clements <glynn at gclements.plus.com> writes:
> 
> [...]
> 
>  >> Is a new D_number_to_RGB(int color, unsigned char &r,&g,&b) fn
>  >> needed in lib/display/tran_colr.c?
> 
>  > Yes. E.g.:
> 
>  > int D_color_number_to_RGB(int color, int &r, int &g, int &b)
>  > {
> 
> 	That looks a lot like C++.  Surely it will work with C89?
> 
>  >     const struct color_rgb *c;
> 
>  >     if (color <= 0)
>  >         return 0;
> 
> 	BTW, is it a GRASS convention to use 0 to indicate failure?
> 	Standard C library functions tend to use -1 for failure, while
> 	using non-negative values to indicate success.

The SUBMITTING file in the source code says:

8.  Exit status is defined as EXIT_SUCCESS or EXIT_FAILURE, e.g.

     {
       ...
       if (G_parser (argc, argv))
           exit (EXIT_FAILURE);

       ...
       exit (EXIT_SUCCESS);
     }

AFAIU, these are defined in stlib as being respectively 0 and 1.

Moritz