Re: Builtin read with -n0 or -N0 (nchars == 0) behaves as a read with no -n/-N argument

[dualbus]

On Sun, Jun 04, 2017 at 01:45:42AM +0530, Pranav Deshpande wrote:
[...]
> My solution is to change *line 294* of builtins/read.def.
> 
> Change
> if (code == 0 || *intval < 0* || intval != (int)intval)
> 
> to
> 
> if (code == 0 || i*ntval <= 0* || intval != (int)intval)
[...]

> Is this solution ok?

Yes. That works.


Chet went with the other option though:

  dualbus@debian:~/src/gnu/bash-build$ ./bash -c 'read -n0; echo $?; declare -p 
REPLY'
  0
  declare -- REPLY=""

You can see the change by navigating the `devel' branch of the git repository
in Savannah (commit 1110e30870a8782425067a060d89cc411b014418):

  
http://git.savannah.gnu.org/cgit/bash.git/commit/?h=devel&id=1110e30870a8782425067a060d89cc411b014418

Although there's a problem with the solution:

  dualbus@debian:~$ for sh in bash ~/src/gnu/bash-build/bash ksh93 mksh; do $sh 
-c ': | read -n 0; echo $?'; done
  1
  0
  1
  1

Since the read(2) system call doesn't take place, `read -n 0' doesn't detect
the broken pipe. IMO, it should.

-- 
Eduardo Bustamante
https://dualbus.me/