Re: Process-Shared Mutex (futex) - What is it good for ?

[Peter Wächtler]

Vladimir Zidar wrote:
> On Sun, 2002-06-09 at 11:49, Peter Wächtler wrote:
> 
> 
>>Just for *that*?
>>Do you write programs that reveal from sigsegv with sigsetjmp(3)?
>>
> 
>  No, I do not. But killing the process sounds much like abnormal
> programm termination. Can you feel the word 'abnormal' ? It is opposite
> of normal - be it simple as error condition on file descriptor.
> 

A-prog:               B-prog:

gets write lock
write some data
                        block on read lock
write some data
crashes
                        wants an error indication to repair data magically

So a crashing A-prog is OK for you, but B should get an indication.
Could catch a signal (SIGLOST?) returning -1 with errno=LOCKBROKEN
That would be possible with futex.

That is a case for writing data to a file - what about linked lists
in memory?