Charles-François Natali <neolo...@free.fr> added the comment: > +# A constant likely larger than the underlying OS pipe buffer size. > +# Windows limit seems to be around 512B, and most Unix kernels have a 64K > pipe > +# buffer size: take 1MB to be sure. > +PIPE_MAX_SIZE = 1024 * 1024 > > Hum, I am not sure that the comment is correct. If I understood correctly the > usage of this constant: write PIPE_MAX_SIZE into a blocking pipe must block > because PIPE_MAX_SIZE is greater than the size of the pipe buffer.
Correct. > I don't know what happen if you write PIPE_MAX_SIZE into a nonblocking pipe: > the beginning of the buffer is written and write() returns something lesser > than PIPE_MAX_SIZE? > Correct. Note that it could also fail with EAGAIN, that's why I added an except OSError clause to the write. > You may specify that if you should greater or equal to os.fpathconf(fd, > "PC_PIPE_BUF"). > I don't understand what you mean. It will be greater than PIPE_BUF, which is around 4096 (I think 512 guaranteed by POSIX). > Here you use PIPE_MAX_SIZE*3, not PIPE_MAX_SIZE :-) You can use b'abc' * > (support.PIPE_MAX_SIZE // 3), or b'a' * support.PIPE_MAX_SIZE. > I know, but that's what the original code did, so I kept it. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue12196> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
