test_poll.py currently fails on Monterey (64-bit AIX) because of a difference
in the system poll() function as compared to Linux.
On Linux (and as required by the Signle Unix Specification:
http://www.opengroup.org/onlinepubs/007908799/xsh/poll.html) if you "poll()"
a bogus file descriptor you get a POLLNVAL return value in the 'revents'
field of the structure sent to poll(). This is tested like so in
test_poll.py:
# returns NVAL for invalid file descriptor
FD = 42
try:
os.close(FD)
except OSError:
pass
p = select.poll()
p.register(FD)
r = p.poll()
assert r[0] == (FD, select.POLLNVAL)
Monterey decided to return -1 instead. [Aside: However, 'revents's type is
"short" so the Python interface to poll() (using PyInt_FromLong) actually
interprets that as -32768 instead.]
Questions:
1. Can anybody offer an opinion if this is Python's or Monterey's problem?
2. Can anybody tell me where I can browse the POSIX spec to see if this
breaks POSIX compliance as well?
3. Could someone (Vladimir?) run this test program on a normal AIX box and
tell me what the output is (does the return value == POLLNVAL?)?
----------------------------------------------------------------------
#include <stdio.h>
#include <poll.h>
#define NFDS 1
int main(void)
{
struct pollfd ufds[NFDS];
int pollResult;
printf("hello\n");
/* poll for any event on a bogus file descriptor */
ufds[0].fd = 42;
ufds[0].events = POLLIN | POLLPRI | POLLOUT;
pollResult = poll(ufds, NFDS, -1);
if (pollResult != 1) {
printf("*** poll result was %d, I expected 1.\n", pollResult);
}
printf("ufds[0].revents = %hd\n", ufds[0].revents);
printf("POLLNVAL = %ld\n", POLLNVAL);
return 0;
}
----------------------------------------------------------------------
Thanks,
Trent
--
Trent Mick
TrentM@ActiveState.com
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