On Sat, Oct 12, 2024 at 21:43:39 -0400, I mistakenly wrote:
> See the ":" followed by two spaces? Unlike systemctl, well-behaved
> programs set "errno" when they puke, and that setting is turned into
> a more-or-less useful error message like "Permission denied".
> "$!" would have held that message.
>> On Sat 12 Oct 2024 at 22:23:31 (-0400), Greg Wooledge replied:
> I don't think this is correct. A *function* can set errno (a global
> variable in C), in addition to returning a value. A process can't,
> unless there has been some major change to the Unix process model that
> I've missed.
You're right, keyboard in motion before brain in gear. Since I don't
have systemctl installed, the system() *function* failed when it tried to
exec a non-existent program and correctly set "$!" to "No such file
or directory".
If I call 'system("/bin/mkdir", "/etc/something")' as myself, the
/bin/mkdir *process* handles errno and prints "Permission denied".
All system() sees is a non-0 exit code.
Removing the --quiet flag and using something like safesys() would:
* let systemctl write something (hopefully an error message),
* show exactly what arguments are being passed to it, and
* show its exit value.
--
Karl Vogel I don't speak for anyone but myself
In [the movie] "Seven", I put it in my contract:
The wife's head stays in the box.
--Brad Pitt on early contract negotiations
