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digitalmars.D - Losing 32 bits of a void pointer

reply "sumo" <sumitraja gmail.com> writes:
I am using D & epoll on Fedora 3.12.10-300.fc20.x86_64 and am 
running into a very odd issue.

The data.ptr value of the epoll_event struct when it comes back 
from the epoll_wait call seems to have lost the top 32 bits.

GDB session produced the following:

Before epoll

$3 = {events = 1, data = {ptr = 0x7ffff7ee2e80, fd = -135385472, 
u32 = 4159581824, u64 = 140737352969856}}

(gdb) x/20g ev
0x7ffff7ee5ff0: 0x0000000000000001      0x00007ffff7ee2e80
0x7ffff7ee6000: 0x0000000000000000      0x0000000000000000

After epoll
$4 = {events = 1, data = {ptr = 0xf7ee2e80, fd = -135385472, u32 
= 4159581824, u64 = 4159581824}}

0x7fffffffe0e0: 0x0000000000000001      0x00000000f7ee2e80
0x7fffffffe0f0: 0x0000000000000001      0x0000000000000000

A similar gdb session with a simple C program produced the 
following:
Before epoll
$1 = {events = 1, data = {ptr = 0x7fbe184d9d00, fd = 407739648, 
u32 = 407739648, u64 = 140454428253440}}

after epoll
$2 = {ptr = 0x7fbe184d9d00, fd = 407739648, u32 = 407739648, u64 
= 1404544282534

Source is at 
https://bitbucket.org/sumitraja/sioford/src/64ee53513876c1763a5e04b9611da64a5d96cced/source/devent/ev
ntqueue.d?at=master 
with break points at eventqueue.d:238 and eventqueue.d:253

I can't figure out what exactly I am doing wrong here so any 
insights would be of great help. I have seen the issue on Debian 
with a 3.2 kernel as well. Happens with both "DMD64 D Compiler 
v2.064" and the Fedora repository version of "LDC - the LLVM D 
compiler (0.12.0)" (Release     : 53.20130805git967b986.fc20).

Thanks

Sumit
Feb 18 2014
next sibling parent "sumo" <sumitraja gmail.com> writes:
On Wednesday, 19 February 2014 at 02:39:39 UTC, sumo wrote:
 I am using D & epoll on Fedora 3.12.10-300.fc20.x86_64 and am 
 running into a very odd issue.

For giggles the D kevent version on FreeBSD has no problems (80079af00 is pointer to the event object): Before kevent: 0x800799f40: 0x0000000000000007 0x000000000005ffff 0x800799f50: 0x0000000000000000 0x000000080079af00 <--- 0x800799f60: 0x00000000004fdca0 0x0000000000000000 0x800799f70: 0x000000080079af80 0x0000000000000000 0x800799f80: 0x00000000004fcc60 0x0000000000000000 0x800799f90: 0x0000000000000000 0x0000000000000000 0x800799fa0: 0x0000000000508ae0 0x0000000000000000 0x800799fb0: 0x00000000d2040200 0x0000000000000000 0x800799fc0: 0x00000000005141a0 0x0000000000000000 0x800799fd0: 0x0000000800798fc0 0x0000000801817070 After kevent: 0x7fffffffd778: 0x0000000000000007 0x000000000000ffff 0x7fffffffd788: 0x0000000000000001 0x000000080079af00 <--- 0x7fffffffd798: 0x0000000800798f40 0x00007fffffffd7c0 0x7fffffffd7a8: 0x000000000041deb0 0x000000080079af80 0x7fffffffd7b8: 0x0000000800798f40 0x00007fffffffd850 0x7fffffffd7c8: 0x00000000004222a3 0x0000000000405990 0x7fffffffd7d8: 0x00007fffffffd82f 0x0000000800798f40 0x7fffffffd7e8: 0x0000000000000000 0x0000000000422440 0x7fffffffd7f8: 0x000000080079af80 0x0000000000000000 0x7fffffffd808: 0x0000000000422380 0x0000000001807000 I couldn't get gdb to print the actual structure - <incomplete type>
Feb 18 2014
prev sibling next sibling parent "sumo" <sumitraja gmail.com> writes:
On Wednesday, 19 February 2014 at 02:39:39 UTC, sumo wrote:
 I am using D & epoll on Fedora 3.12.10-300.fc20.x86_64 and am 
 running into a very odd issue.

For anyone who runs in to this, it is a because the epoll_event struct is packed on x86_64 bits processors. Have created a pull for druntime.
Mar 24 2014
prev sibling next sibling parent "deadalnix" <deadalnix gmail.com> writes:
On Monday, 24 March 2014 at 20:45:13 UTC, sumo wrote:
 On Wednesday, 19 February 2014 at 02:39:39 UTC, sumo wrote:
 I am using D & epoll on Fedora 3.12.10-300.fc20.x86_64 and am 
 running into a very odd issue.

For anyone who runs in to this, it is a because the epoll_event struct is packed on x86_64 bits processors. Have created a pull for druntime.

Thumb up !
Mar 24 2014
prev sibling next sibling parent Andrej Mitrovic <andrej.mitrovich gmail.com> writes:
On 3/24/14, sumo <sumitraja gmail.com> wrote:
 For anyone who runs in to this, it is a because the epoll_event
 struct is packed  on x86_64 bits processors. Have created a pull
 for druntime.

I'm really surprised this wasn't caught sooner. I thought epoll was supposed to be popular. Maybe not so much in the context of D?
Mar 24 2014
prev sibling parent "Paolo Invernizzi" <paolo.invernizzi no.address> writes:
On Monday, 24 March 2014 at 23:16:38 UTC, Andrej Mitrovic wrote:
 On 3/24/14, sumo <sumitraja gmail.com> wrote:
 For anyone who runs in to this, it is a because the epoll_event
 struct is packed  on x86_64 bits processors. Have created a 
 pull
 for druntime.

I'm really surprised this wasn't caught sooner. I thought epoll was supposed to be popular. Maybe not so much in the context of D?

Here we are using epoll a lot, but right now we have custom declarations for external API. --- Paolo
Mar 24 2014