libTagList

#define ATTR_COLOR (TAG_USER|0x01L)
#define ATTR_SHAPE (TAG_USER|0x02L)
#define ATTR_LTYPE (TAG_USER|0x03L)
#deinfe ATTR_WIDTH (TAG_USER|0x04L)
#define ATTR_HEIGHT (TAG_USER|0x05L)

#define SHAPE_DOT 0
#define SHAPE_BOX 1
#define SHAPE_CIRCLE 2


char *defaultcol="#008080";

/* Varargs stub */
int TestFunc( int x, int y, ... )
{
	struct TagItem *tags=&y+1;
	return( TestFuncA( x, y, tags ) );
}

int TestFuncA( int x, int y, struct TagItem *tags )
{
	char *color;

	/* If a tag with ATTR_COLOR is found it's value is used */
	/* otherwise the default value will be used */
	color=(char *)GetTagData( ATTR_COLOR, defaultcol, tags );
	...
	DoSomeImportantStuff(TM);
	...
	return(...);
}

void main( void )
{
	TestFunc( 40, 25,
		ATTR_COLOR,"#804000",
		ATTR_SHAPE, SHAPE_BOX,
		ATTR_WIDTH, 19,
		ATTR_HEIGHT, 25,
		TAG_DONE
	);
}