[GRASS-dev] lib/pngdriver Mingw compile error

[Glynn Clements]

Paul Kelly wrote:

> I've just been experimenting with compiling GRASS under Mingw32 on 
> Windows. Half my time's been spent ripping out Mingw-specific hacks in the 
> Makefiles and configure scripts as they make it impossible to see what's 
> really going on. Anyway it seems to be compiling and running for the most 
> part OK (well as well as can be expected) using shared dlls for the GRASS 
> internal libraries, but am having the following problem with lib/pngdriver 
> (compiler output reproduced below). I might be able to get to the bottom 
> of it but thought perhaps there might be a chance of resolving it much 
> more quickly if posting to the list? A few people have done MinGW compiles 
> now. I'm using libpng 1.2.12.

> OBJ.i686-pc-mingw32/Color_table.o(.text+0x20f): In function `init_color_table': c:/grass/grass6/lib/pngdriver/Color_table.c:77: variable 'standard_colors_rgb' can't be auto-imported. Please read the documentation for ld's --enable-auto-import for details.
> OBJ.i686-pc-mingw32/Color_table.o(.text+0x223):c:/grass/grass6/lib/pngdriver/Color_table.c:77: variable 'standard_colors_rgb' can't be auto-imported. Please read the documentation for ld's --enable-auto-import for details.

According to the Info file, you need to do something like:

void init_color_table(void)
{
	volatile const struct color_rgb *std_rgb = standard_colors_rgb;
	int colorindex;

	if (true_color)
		init_colors_rgb();
	else
		init_colors_indexed();

	/* Generate lookup for "standard" colors */
	for (colorindex = 1; colorindex <= MAX_COLOR_NUM; colorindex++)
		LIB_assign_standard_color(
			colorindex,
			DRV_lookup_color(
				(int) std_rgb[colorindex].r,
				(int) std_rgb[colorindex].g,
				(int) std_rgb[colorindex].b)) ;
}

The alternative is to add a function to libgis, e.g.:

const struct color_rgb *get_standard_color_rgb(int index)
{
	return &standard_colors_rgb[index];
}

and use that instead of accessing the array directly.

-- 
Glynn Clements <glynn at gclements.plus.com>