On 1月13日, 下午2时03分, jave...@gmail.com wrote: > Hi, > > I encountered a very strange issue in file flush operation in Windows. > Here's the scenario of my application: > > 1. The main thread of my application will create makefiles > sequentially. > 2. Once a makefile is generated, launch a new process calling > nmake.exe to run it. The main thread then create another makefile > until no more makefiles to create. > 3. The number of new processes is limited by command line options. > > My application has been running for almost a year without any problem. > But, after I made some changes recently to the content of makefile > generated, "nmake.exe" in separate process sometimes complains that > the makefile is not found. When I went into the directory, the > makefile did exist there. > > Because I didn't change any thing related to file creation and the new > makefiles are a little bit less than before, I guessed that the > makefile just created hasn't been flushed to disk because of size > change so the new process could not see it in a short time. > > So I decided add code to force flush file buffer after writing the > file content (I didn't flush the file explicitly before). I did it > like below: > > Fd = open(File, "w") > Fd.write(Content) > Fd.flush() > os.fsync(Fd.fileno()) > Fd.close() > > The strangest thing happened. The "makefile" missing happened more > frequently than no flush operation. I searched the web but no answer > there. > > Finally I tried to use Windows file API to create the file via pywin32 > extension. The problem's gone. > > import win32file > Fd = win32file.CreateFile( > File, > win32file.GENERIC_WRITE, > 0, > None, > win32file.CREATE_ALWAYS, > win32file.FILE_ATTRIBUTE_NORMAL, > None > ) > win32file.WriteFile(Fd, str(Content), None) > win32file.FlushFileBuffers(Fd) > win32file.CloseHandle(Fd) > > I tried writing small python extension in C to make use Windows API to > create file like above. It also works well, even I removed the > FlushFileBuffers() calling. > > Did anyone encounter such problem before? Did I do something wrong in > Python file operation? If not, I believe that there's a bug in Python > file buffer mechanism. I'd appreciate any help or hints. > > Cheers, > Javen
And the same application has no such problem in Linux. -- http://mail.python.org/mailman/listinfo/python-list
