Re: [9fans] nil, and the danger of zero

Re: [9fans] nil, and the danger of zero

[lucio]

> which is why this code has
> been just like that in plan 9 for 15 or more years.

Please arrange to change it :-)

++L

[9fans] nil, and the danger of zero

[erik quanstrom]

so, as it turns out, not all zeros do the same thing to the stack.....  pfffft.
at least it's a simple reason why venti won't run.

; diffy -c ../boot/local.c
/n/dump/2014/0403/sys/src/nix/boot/local.c:212,218 - ../boot/local.c:212,218
  				f[2] = "tcp!127.1!8000";
  			}
  			configloopback();
- 			run("/boot/venti", "-c", f[0], "-a", f[1], "-h", f[2], 0);
+ 			run("/boot/venti", "-c", f[0], "-a", f[1], "-h", f[2], nil);
  			/*
  			 * If the announce address is tcp!*!foo, then set
  			 * $venti to tcp!127.1!foo instead, which is actually dialable.
/n/dump/2014/0403/sys/src/nix/boot/local.c:233,239 - ../boot/local.c:233,239

  	/* start fossil */
  	print("fossil(%s)...", partition);
- 	run("/boot/fossil", "-f", partition, "-c", "srv -A fboot", "-c", "srv -p fscons", 0);
+ 	run("/boot/fossil", "-f", partition, "-c", "srv -A fboot", "-c", "srv -p fscons", nil);
  	fd = open("#s/fboot", ORDWR);
  	if(fd < 0){
  		print("open #s/fboot: %r\n");

- erik

Re: [9fans] nil, and the danger of zero

[Nick Owens]

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On Fri, Apr 04, 2014 at 01:35:05AM -0400, erik quanstrom wrote:
> so, as it turns out, not all zeros do the same thing to the stack.....  pfffft.
> at least it's a simple reason why venti won't run.
> 

(void *)0 is certainly not the same as 0.
depending on architecture and compiler, of course.


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Re: [9fans] nil, and the danger of zero

[erik quanstrom]

> (void *)0 is certainly not the same as 0.
> depending on architecture and compiler, of course.

it's not the compiler, it's the type model, which if anything
is tied to the hardware.  you just won't have this sort of
problem on a 32-bit machine.  which is why this code has
been just like that in plan 9 for 15 or more years.

- erik