Re: Emacs on QNX

[Paul Eggert]

Thanks for looking into a QNX port.

Elad Lahav wrote:

> There is still a stub that returns -1 and sets errno to
> ENOMEM, but the Emacs code doesn't check for that, and interprets the
> result as the address 0xffffffffffffffff.

Which part of the Emacs code is that? Is this the call in src/unexelf.c? If so, 
I can fix that.

> To overcome the problem, I wrote a naive implementation of sbrk() in a
> dynamically-linked library

Although that's clever, I'm hoping that we can port to QNX the same way we port 
to Cygwin, as Cygwin already uses a fake sbrk. (Eventually Emacs has got to stop 
using sbrk, but we don't have an adequate solution to that bigger problem yet.)

Does the attached patch work for you instead?

> +    CFLAGS="$CFLAGS -D__NO_EXT_QNX"

Could you fill us on on what __NO_EXT_QNX does? The symbol I see mentioned in 
public discussions is _QNX_SOURCE. What is the difference between those two 
symbols, and why is __NO_EXT_QNX preferable here? What happens if you leave it out?

qnx.diff
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