Re: [png-mng-implement] png_set_gamma always sets PNG_GAMMAif alpha channel present

[Bob F. <bfr...@si...>]

On Mon, 29 Jun 2009, John Bowler wrote:
>
> #define MyLUT (myLUT())
>
> LUT *myLUT() {
> 	static thisLUT[256]; /* whatever is required */
> 	static int inited = 0;
> 	if (!inited)
> 		initThisLUT(thisLUT);
> 	return thisLUT;
> }
>
> Then do not attempt to wade through a mass of conditions to determine if the
> LUT must be initialized before processing starts, just make sure that the
> code that accesses the LUT uses a local variable to hold the pointer:

The problem is that this approach is not thread safe.  Threads are the 
future.  Putting thread unsafe code in a library without a means to 
make it thread safe is a serious problem.

Bob
--
Bob Friesenhahn
bfr...@si..., http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/