[Toybox] [PATCH] Use NULL rather than 0 in vargs.

[Rob Landley]

My first weekend back home in Austin, and GOING to pick something to
spend some time on, and I guess it's this. :)

On 12/05/2017 11:32 AM, enh wrote:
> want me to switch to arrays? (and if so, presumably using ARRAY_LEN
> rather than an explicit end element?)

I can do it as part of my cleanup pass. Let's see...

You sent in commit eb7e847adcec removing periods from help text and then
submit a command with periods in help text. :)

There is no tests/stty.test. I'm not entirely sure how to make one
either. Um... (Even with a qemu instance to test under, I'd need a pty
wrapper to automate testing of this. I've considered _writing_ a pty
wrapper for a while, it's in the "implement screen" bucket. And other
stuff like set baud and print baud... if it's the same implementation
setting and checking you're not showing that it's _right_, just that it
matches...)

One of the reasons I hadn't done stty yet is I'm not sure how much of
the serial settings are relevant in 2017. Every serial port in the world
was 8-n-1 already in the 80's, so the even/odd/parity stuff is a
historical relic.

Um, shouldn't stty operate on _stdout_ instead of stdin when modifying?
Hmmm... no, I guess not, the other one isn't doing so and "cooked/raw"
are stdin questions anyway. So yes, open stdin for _writing_. Which
presumably means the shell that launched us has to have opened stdin for
writing if it's a tty? I should write that down somewhere...

Lots of things can be inlined, starting with do_stty().

Trivial code style tweaks: I generally don't put curly brackets around
single lines, and when an if () is multiline I put the curly bracket at
the start of the next line. Space after commas in function arguments
(unless removing some brings it under 80 columns to avoid a line split).

Factor out xtcgetattr() doing the error handling (just into a static
function so it can still use the globals, only two calls but still a win).

You have the baud list in microcom.c already, it should move to lib. And
I already did the bit pattern skipping compression, but I didn't make
the array unsigned short and multiply by 100 safter 57600. (It's the
same logic as the skip.) Query: why do you allow 0 as a baud value? Does
that have some meaning? (The serial ports I've dealt with recently were
all USB so it was a packet protocol, and then the j-core uartlite device
is simple hardware running at a fixed speed, so I'm trying to think when
the last time is I set a serial port speed. Probably the cortex-m board,
but the kernel set the speed of that for me. Makes it kind of hard to
TEST any changes I make here, doesn't it?)

N_TTY is 0 so all the low bounds of get_arg() are zero. I can cheat by
having all the non-option arguments come first, and then when we fall
down to the right point parse the next numerical argument...

We don't actually care about the return value of tcsetattr() as long as
the returned data is right when we tcgetattr() on the next line.

I should check some of this in...

Rob