> On Aug 15, 2023, at 15:42, Takashi Yano <takashi.y...@nifty.ne.jp> wrote: > >> >>> >>> New pipe implementation since cygwin 3.4.x provides the pipes >>> more similar to pipe in command prompt for non-cygwin apps. >> >> What are the differences between these pipes? What changed? > > Many changes. But, the change which triggers this behaviour > is setting FILE_SYNCHRONOUS_IO_NONALERT create option. > > With this option, seekg() of Microsoft library gets success > for pipes, despite it should not I suppose.
On what create is this option specified? I have the seekg() test because on some systems you can seek on stdin when it is being redirected to read from a file, or so I read somewhere. Perhaps I should always buffer stdin on Windows to avoid this problem. I will put some tracing in `test-pipe.c++` to see whether it is currently buffering or not. > > In Linux, man page states that fseek() on pipes will fail. > >>> Since your test case is compiled with cl.exe, it is non-cygwin >>> apps. >> >> When the failure first appeared the bash shell included with Git for Windows >> was being used to run the pipe (`bash -c "cat foo | bar”`). The shell was >> started by ctest which had been run from PowerShell. Is this cygwin or >> non-cygwin? > > It depends on "bar". If bar is compiled with cl.exe or gcc/g++ in > MSYS2 mingw environment, it is non-cygwin app. > >> in >> https://github.com/git-for-windows/git/issues/4464#issuecomment-1671137446 >> the author provided minimal adaption to the reproducer to compile it with >> g++ and reproduced the failure on Cygwin. It looks like the failure happens >> for both cygwin and non-cygwin. It is probably related to the new pipe >> implementation you mentioned. > > Is there any failure case where the pipe reader is cygwin (or MSYS2) > binary? We’ve only tested non-Cygwin consumers. When the author of the above GitHub issue comment was testing on Cygwin he compiled the consumer with mingw-w64 g++. Regards -Mark
signature.asc
Description: Message signed with OpenPGP
-- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
