[dtrace-discuss] Detect stack size

[Casper.Dik at Sun.COM]

>Casper.Dik at Sun.COM wrote:
>>> why not? as far as I understand, getrlimit and setrlimit are in standard 
>>> C lib as welland they have been used to dynamically get the soft an hard
>>> limit of the resources in the context of the current process.
>>>     
>>
>> Yes, but they don't work for the stack size parameters.
>>   
>they work for stack size as well as cpu time,maximum file size, data 
>size, core file size etc.
>are all resources that are allowed to be tuned in the given process's 
>context.
>I recall only use of RLIMIT_STACK resource so far.


Perhaps you should read the manual page:

     RLIMIT_STACK    The maximum size of  a  process's  stack  in
                     bytes.  The  system  will  not automatically
                     grow the stack beyond this limit.

                     Within a process, setrlimit() will  increase
                     the  limit  on  the  size of your stack, but
                     will not move  current  memory  segments  to
                     allow for that growth. To guarantee that the
                     process stack can grow  to  the  limit,  the
                     limit must be altered prior to the execution
                     of the process in which the new  stack  size
                     is to be used.

                     Within a multithreaded process,  setrlimit()
                     has  no  impact  on the stack size limit for
                     the calling thread if the calling thread  is
                     not  the  main thread. A call to setrlimit()
                     for  RLIMIT_STACK  impacts  only  the   main
                     thread's stack, and should be made only from
                     the main thread, if at all.


In short: no effect and thread stacks and little or no effect
on the stack of the currently executing process (see the second
hald of the second paragraph.

Casper