Re: mmapping of /dev/zero always fails on darwin

[Peter O'Gorman]

Derek Price wrote:

> I don't suppose you could come up with a configure test or a short C
> program that fails to compile (preferrably) or run (if necessary) to
> spot this, short of actually switching on the system name or something
> similar?

The test would have to be a run test, which would mean having a 
cross-compile alternative switching on the system name (this is why gcc 
switches on name).

Just doing the same thing as gnulib does will show the failure:

int main(){
        void * address = NULL;
        static int fd =-1;
        int ret = 0;
        fd = open ("/dev/zero",O_RDONLY,666);
        ret = mmap (NULL, 4096, PROT_READ | PROT_WRITE, MAP_FILE | 
MAP_PRIVATE, fd, 0);
        if (ret != MAP_FAILED) return 0;
return 1;
}

Hope this helps,
Peter