resizing window when using "bc" in interactive mode

[Bill Cole]

On 2024-08-11 at 18:34:30 UTC-0400 (Sun, 11 Aug 2024 18:34:30 -0400)
Richard L. Hamilton <rlhamil at smart.net>
is rumored to have said:

> Semi-understandable. The default system action for SIGWINCH is to do 
> nothing; i.e. only programs that catch it are even aware of it. That 
> would usually be programs like text editors that do full-window text 
> handling, and probably need to re-fetch the current size and redraw on 
> window size change.

Right. It is clearly a bug.

> Makes me wonder if they're using libncurses or something like it, but 
> not using it properly.

The Apple build uses libedit. If I build the current version source with 
or without --enable-editline, I cannot reproduce the bug. Looks like an 
Apple-specific problem.


> From sigaction(2) on Monterey, the signals that do nothing by default 
> (although in the case of SIGCHLD at least, ignoring it is a bit 
> different from the default):
>
>      SIGURG          discard signal          urgent condition present 
> on socket
>      SIGCONT         discard signal          continue after stop
>      SIGCHLD         discard signal          child status has changed
>      SIGIO           discard signal          I/O is possible on a 
> descriptor
>      SIGWINCH        discard signal          Window size change
>      SIGINFO         discard signal          status request from 
> keyboard

Right, but anything that does interactive command line editing like bc 
needs to handle SIGWINCH.

> I'm not seeing the problem on Ventura, which uses the Gavin Howard bc 
> (if perhaps not the same version as on Sonoma, which I don't have).

Firmly setting the bug in Apple's lap.


>
>> On Aug 11, 2024, at 10:37, Bill Cole 
>> <macportsusers-20171215 at billmail.scconsult.com> wrote:
>>
>> On 2024-08-11 at 03:08:11 UTC-0400 (Sun, 11 Aug 2024 02:08:11 -0500)
>> Ryan Carsten Schmidt <ryandesign at macports.org 
>> <mailto:ryandesign at macports.org>>
>> is rumored to have said:
>>
>> On Aug 11, 2024, at 00:03, Richard L. Hamilton wrote:
>>
>> The MacPorts version uses MacPorts supplied libraries (other than 
>> libSystem). The macOS version uses macOS supplied libraries. 
>> (ultimately from the same open source projects, but potentially 
>> different versions and build options, so not identical code)
>>
>> It's *not* the same software. MacPorts has GNU bc 1.07 which is 
>> licensed GPL-3. macOS used to have GNU bc 1.06 released back in 2000 
>> under GPL-2. Apple has switched to someone else's bc implementation 
>> in recent macOS probably because as we know Apple is allergic to 
>> GPL-3.
>>
>> The macOS bc is Gavin Howard's version which is also used in FreeBSD. 
>> It integrates both the GNU additions to the POSIX-standard bc and its 
>> own additions, some of which came from the original BSD bc. There has 
>> been a steady trickle of bug fixes since the version Apple ships on 
>> Sonoma, some of which reference macOS.
>>
>> Looking at the man page, I'd bet that exiting when the terminal 
>> geometry changes is understandable, since making that change sends a 
>> WINCH signal and bc resets on signals for which it has no handler. 
>> That gap seems like a bug to me, but one to report to the author or 
>> Apple.
>>
>>
>>    bill at scconsult.com <mailto:bill at scconsult.com> or 
>> billcole at apache.org <mailto:billcole at apache.org>
>>    (AKA @grumpybozo at toad.social <mailto:grumpybozo at toad.social> and 
>> many *@billmail.scconsult.com addresses)
>>    Not Currently Available For Hire


-- 
Bill Cole
bill at scconsult.com or billcole at apache.org
(AKA @grumpybozo at toad.social and many *@billmail.scconsult.com 
addresses)
Not Currently Available For Hire
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