[9fans] alarm() and threads..

[9fans] alarm() and threads..

[ISHWAR RATTAN]

What is the behavior of using alarm() in one of the threads
in a multi-threaded program? Which will thread will get the
note? Or it is undefined -- alarm() can be used at process
level.

Also, where can I find sample code to handle terminal
abort/interrupt?

-ishwar

Re: [9fans] alarm() and threads..

[Russ Cox]

> What is the behavior of using alarm() in one of the threads
> in a multi-threaded program? Which will thread will get the
> note?

Threads don't get notes.  Processes do.  The function you
register with threadnotify will run in the same proc that
got the note, and if that proc was in a system call, that
system call will have been interrupted, regardless of which
thread inside the proc was running the system call.

If your code looks like:

    alarm(10);
    read();
    alarm(0);

then you can be sure that your thread's read is the one that
will be interrupted should the alarm go off.

> Also, where can I find sample code to handle terminal
> abort/interrupt?

Depends on what you mean by this.  If you mean when
the user types Delete to kill a program, that turns into
a "interrupt" note.

Russ

Re: [9fans] alarm() and threads..

[ISHWAR RATTAN]

On Tue, 6 Dec 2005, Russ Cox wrote:

> Depends on what you mean by this.  If you mean when
> the user types Delete to kill a program, that turns into
> a "interrupt" note.

How can it be acheived in context in writing a program
to handle this condition?

-ishwar

Re: [9fans] alarm() and threads..

[Russ Cox]

> > Depends on what you mean by this.  If you mean when
> > the user types Delete to kill a program, that turns into
> > a "interrupt" note.
>
> How can it be acheived in context in writing a program
> to handle this condition?

What do you want the program to do when the user types Delete?

Russ

Re: [9fans] alarm() and threads..

[ISHWAR RATTAN]

On Wed, 7 Dec 2005, Russ Cox wrote:

> What do you want the program to do when the user types Delete?
Generally a clean up, closing open files etc.

-ishwar

Re: [9fans] alarm() and threads..

[Russ Cox]

> > What do you want the program to do when the user types Delete?
> Generally a clean up, closing open files etc.

Then install a handler with threadnotify
and have it clean up if strcmp(note, "interrupt")==0.

Russ