Edit report at https://bugs.php.net/bug.php?id=75538&edit=1
ID: 75538
Updated by: requinix@php.net
Reported by: samuel dot chemla at orange dot com
Summary: stream_set_blocking() always returning false for
files on windows
Status: Closed
Type: Bug
Package: Streams related
Operating System: Windows
PHP Version: 7.1.11
Assigned To: ab
Block user comment: N
Private report: N
New Comment:
> Can you provide a working example of non blocking file access on linux?
Feel free to submit a bug report on how stream_set_blocking() with a local file, on Linux, appears
to work when ultimately the operating system is not respecting the setting. Because that's not
what this report was about.
Previous Comments:
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[2018-11-19 09:02:20] samuel dot chemla at orange dot com
Well, in http://man7.org/linux/man-pages/man2/open.2.html:
>O_NONBLOCK or O_NDELAY
When possible, the file is opened in nonblocking mode.
Neither the open() nor any subsequent operations on the file
descriptor which is returned will cause the calling process to
wait.
Note that this flag has no effect for regular files and block
devices;
"This flag has no effect for regular files".
I've done some tests on linux, reading files.
* stream_set_blocking($handle, false) return true, so i expected it to work.
* then i tries fread($handle, $length) with many different $length sizes, and fread always returned
the required length, event on a busy system, with a slow rotating drive
--> So I assume stream_set_blocking() do **not** work on linux either.
Am I wrong?
Can you provide a working example of non blocking file access on linux?
------------------------------------------------------------------------
[2018-11-16 17:06:57] requinix@php.net
> My understanding is that stream_set_blocking does *not* work for regular files, whatever the OS
> is.
Linux and BSD may or may not support it, but all seem to support setting the flag.
http://man7.org/linux/man-pages/man2/open.2.html
> When possible, the file is opened in nonblocking mode.
> Note that this flag has no effect for regular files and block devices
https://linux.die.net/man/2/open
> When possible, the file is opened in nonblocking mode.
https://www.freebsd.org/cgi/man.cgi?sektion=2&query=open
> O_NONBLOCK do not block on open
But Windows' _open doesn't have a "_O_NONBLOCK" or other non-blocking flag.
https://msdn.microsoft.com/en-us/library/z0kc8e3z.aspx
In fact as far as I can tell, it doesn't have an fcntl (though winsock has something equivalent
for sockets?) or O_NONBLOCK flag anywhere. I think that's the problem: not that Windows
doesn't allow setting non-blocking on files but that it can't.
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[2018-11-16 13:54:36] samuel dot chemla at orange dot com
I'm reopening this because I think it requires clarification
------------------------------------------------------------------------
[2018-11-09 20:59:30] samel dot chemla at orange dot com
Hi!
I know this is an old topic, but I just saw the doc http://php.net/manual/en/function.stream-set-blocking.php
was updated with that note: "On Windows, this has no affect on local files. Non-blocking IO for
local files is not supported on Windows."
My understanding is that stream_set_blocking does *not* work for regular files, whatever the OS is.
Then if this is correct, then:
* the windows note should be removed from the documentation,
* this statement should be fixed: "This function works for any stream that supports
non-blocking mode (currently, regular files and socket streams)."
* stream_set_blocking() should return false, whatever the OS is. IE linux implementation should be
fixed because actually it returns true.
Can you clarify?
Regards.
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[2018-01-26 16:47:03] ab@php.net
Closing as per request. Thanks for documenting, Matt.
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