From: "David A. Black" <dblack@...>
Date: 2008-09-06T07:10:46+09:00
Subject: [ruby-core:18465] Re: Global constants and other magic in 1.9 stdlib

Hi --

On Sat, 6 Sep 2008, Yukihiro Matsumoto wrote:

> Hi,
>
> In message "Re: [ruby-core:18461] Re: Global constants and other magic in 1.9	stdlib"
>    on Sat, 6 Sep 2008 01:03:04 +0900, Paul Brannan <pbrannan@atdesk.com> writes:
>
> |$_ is thread-local, but $? really is global:
> |
> |  rb_define_readonly_variable("$?", &rb_last_status);
> |
> |I'm sure there's a good reason, but I don't know what it is. (maybe
> |something to do with calling Process.wait from a signal handler?)
>
> Since $? is a result from waitpid, which is not always bound to a
> thread.

I'm wondering if I'm misinterpreting this as thread-local $? behavior,
and if it isn't, then what's accounting for the two $?'s:

>> t = Thread.new { system("ddddd"); Thread.stop; puts $? }
=> #<Thread:0x3b1b7c run>
>> system("date")
Fri Sep  5 18:12:32 EDT 2008
=> true
>> $?
=> #<Process::Status: pid 344 exit 0>
>> t.run
=> #<Thread:0x3b1b7c run>
pid 343 exit 127


David

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