Re: [PATCH] Mac OS X 10.5 does not require the OLD_ICONV flag set

["Blake Ramsdell" <blaker@gmail.com>]

On 11/2/07, David Symonds <dsymonds@gmail.com> wrote:
> It would probably be most appropriate for the autoconf script. Now
> that I look at configure.ac, there's already a test for iconv in
> there; is it not used?

The crux of this problem is that the prototype for iconv in
/usr/include/iconv.h is different between OS X 10.4 and OS X 10.5. So
the "right thing" is definitely to determine what is in the function
prototype, and then act accordingly.

>From OS X 10.4.10:

#define _LIBICONV_VERSION 0x0109    /* version number: (major<<8) + minor */
...
extern size_t iconv (iconv_t cd, const char* * inbuf, size_t
*inbytesleft, char* * outbuf, size_t *outbytesleft);

>From OS X 10.5:

#define _LIBICONV_VERSION 0x010B    /* version number: (major<<8) + minor */
...
size_t iconv (iconv_t /*cd*/,
        char ** __restrict /*inbuf*/,  size_t * __restrict /*inbytesleft*/,
        char ** __restrict /*outbuf*/, size_t * __restrict /*outbytesleft*/);

So what happened in git is that someone put in OLD_ICONV to
dynamically adjust the const-ness of parameter 2 to the iconv
function, and the way they chose to do that is to identify the OS
(more accurately, the kernel), and then I went and furthered that by
identifying the version.

Now that I look at it further, it seems that yanking OLD_ICONV
altogether is a better approach, and to just check _LIBICONV_VERSION
to make sure it's "new enough". Now, I'm not sure what that comparison
would be, but we know that "later than 0x0109" is a good start. Based
on the version difference between OS X 10.4 and 10.5 I note that there
is only 0x010A intervening.

This strategy presumes that this const parameter was const all the way
up to a particular point, and then stopped being const, which is
probably a reasonable assumption.

Blake
-- 
Blake Ramsdell | http://www.blakeramsdell.com