"Ken Borgendale" <kwb@betasvm2.vnet.ibm.com> (05/20/91)
The stack for a thread belongs to the parent thread, which passes it in _beginthread (or DosCreateThread). The parent thread can wait or check for the death of the child and then do what it likes with the storage associated with the child thread's stack.
feustel@netcom.COM (David Feustel) (05/21/91)
The exiting thread can enter a critical section, set a flag saying the stack is free, and then do a programexit call. This works for single process code only. -- David Feustel, 1930 Curdes Ave, Fort Wayne, IN 46805, (219) 482-9631 EMAIL: feustel@netcom.com or feustel@cvax.ipfw.indiana.edu
kenr@arcade.uucp (Ken Reneris) (05/25/91)
| The stack for a thread belongs to the parent thread, which passes it | in _beginthread (or DosCreateThread). The parent thread can wait | or check for the death of the child and then do what it likes with | the storage associated with the child thread's stack. The ways to do this seem to be: o The main thread can poll for when the sub-thread has called DosExit. (You can tell if a TID is bad by calling various api - like, DosGetPrty) o The sub-thread can queue up it's strucutre before calling DosExit to say 'hey, I'm dead'. ... DosEnterCritSec add myself to queue (or even free the memory) (kick semaphore to notify main thread) DosExit // Note you don't call DosExitCritSec. It's automatically // exited when the thread terminates. This allows you to // do your cleanup and without having one of your other // threads pick it up half way. // // Note2: the queue has to be per-process, since that's all // the EnterCritSec provides o If you simply want to set a flag, (Or are using a word LL and you queue up with xchg) you can do the same thing without calling EnterCritSec: mov ss:sp to 4 byte dumby stack area set flag saying our stack has been freed and it can be re-used. call DosExit Hmm.. since I've never read that DosExit doesn't require any R3 stack I'm not sure if this is legal. The basic idea is that more then one thread can use the '4 byte stack' to call DosExit. Since the threads never return and are passing in the same parameters, it's not a problem that they are using the same memory for their stacks. Beyond this, my code normally doesn't free threads and stacks right away. (Allocating one is cheap, but not free). A thread waits until it's not needed for some amount of time (10 seconds), then it frees itself. - Ken -- {uunet,uw-beaver}!microsoft!arcade!kenr
feustel@netcom.COM (David Feustel) (05/26/91)
DosExit plays with the Stack before a final exit is achieved. If you mess with the stack DosExit may not terminate properly. -- David Feustel, 1930 Curdes Ave, Fort Wayne, IN 46805, (219) 482-9631 EMAIL: feustel@netcom.com or feustel@cvax.ipfw.indiana.edu