[PATCH v8] Cygwin: pipe: Switch pipe mode to blocking mode by default

[Takashi Yano]

On Thu, 31 Oct 2024 11:15:59 +0100
Corinna Vinschen wrote:
> Hi Takashi,
> 
> On Oct 31 17:36, Takashi Yano wrote:
> > Hi Corinna,
> > 
> > On Mon, 28 Oct 2024 12:57:05 +0100
> > Corinna Vinschen wrote:
> > > On Oct 28 20:25, Takashi Yano wrote:
> > > > Is the test case I used different from yours? Without the 2nd arg,
> > > > $ ./a.exe 40000
> > > > pipe capacity: 65536
> > > > write: writable 1, 40000 25536
> > > > write: writable 1, SIGALRM 24576 960
> > > > write: writable 0, SIGALRM -1 / Interrupted system call
> > > 
> > > This is the same testcase I pasted last week:
> > > 
> > >   $ ./x 40000
> > >   pipe capacity: 65536
> > >   write: writable 1, 40000 25536
> > >   write: writable 1, SIGALRM 24576 960
> > >   write: writable 0, SIGALRM 512 448
> > >   write: writable 0, SIGALRM 256 192
> > >   write: writable 0, SIGALRM 128 64
> > >   write: writable 0, SIGALRM 64 0
> > >   write: writable 0, SIGALRM -1 / Interrupted system call
> > > 
> > > So why does it not get into the last else case after calling
> > > pipe_data_available()?  Do you get a different return value
> > > from pipe_data_available()? If so, what and why?
> > 
> > I checked the behaviour in my environment.
> > __builtin_clzl(960) returns 54 in my environment.
> > So, result of
> > 	len1 = 1 << (31 - __builtin_clzl (avail));
> > is undefined. If I modify this to:
> > 	len1 = 1 << (63 - __builtin_clzl (avail));
> > I can get:
> > 
> > $ ./a.exe 40000 1
> > pipe capacity: 65536
> > write: writable 1, 40000 25536
> > write: writable 1, 24576 960
> > write: writable 0, 512 448
> > write: writable 0, 256 192
> > write: writable 0, 128 64
> > write: writable 0, 64 0
> > write: writable 0, -1 / Resource temporarily unavailable
> > 
> > with the commit 686e46ce7148 as well as with my v9 patch.
> > 
> > Could you please fix?
> 
> Yes, I will, but [...]

With your latest patch, my v9 patch works as expected.

$ ./a.exe 40000 1
pipe capacity: 65536
write: writable 1, 40000 25536
write: writable 1, 24576 960
write: writable 0, 512 448
write: writable 0, 256 192
write: writable 0, 128 64
write: writable 0, 64 0
write: writable 0, -1 / Resource temporarily unavailable

Thanks!

Any other suggestions for v9 patch?

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>