Den 2011-04-18 14:23 skrev Peter Rosin:
> Den 2011-04-18 13:43 skrev Peter Rosin:
>> Hi!
>>
>> Using the following STC, I'm seeing what appears to be a memory
>> leak in select(2).
>>
> ----------------8<---(selectleak.c)---------
> #include <sys/time.h>
> #include <fcntl.h>
>
> int
> main(void)
> {
> fd_set fdset;
>
> long flags = fcntl(0, F_GETFL);
> fcntl(0, F_SETFL, flags | O_NONBLOCK);
>
> for (;;) {
> int res;
> char buf[20];
>
> FD_ZERO(&fdset);
> FD_SET(0, &fdset);
> res = select(1, &fdset, NULL, NULL, NULL);
> if (!res)
> continue;
> if (res < 0)
> return 1;
> res = read(0, buf, sizeof(buf));
> if (!res)
> break;
> if (res < 0)
> return 1;
> }
>
> return 0;
> }
> ----------------8<--------------------------
Ok, I'm taking a wild swing at this, and my guess is that the call
sel.cleanup () in cygwin_select prematurely zeros out the cleanup
member of the select_record. The call to sel.poll () then adds
"stuff" to the select_record that really should have been cleaned
up, but isn't since cleanup has already been executed and then
zapped (by select_stuff::cleanup).
But what do I know?
Cheers,
Peter
extern "C" int
cygwin_select (int maxfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
struct timeval *to)
{
select_stuff sel;
fd_set *dummy_readfds = allocfd_set (maxfds);
fd_set *dummy_writefds = allocfd_set (maxfds);
fd_set *dummy_exceptfds = allocfd_set (maxfds);
...
sel.cleanup (); // Too early ???
copyfd_set (readfds, r, maxfds);
copyfd_set (writefds, w, maxfds);
copyfd_set (exceptfds, e, maxfds);
return timeout ? 0 : sel.poll (readfds, writefds, exceptfds);
}
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