On Sat, 18 Oct 2014 18:42:00 -0700, Dan Stromberg wrote: > On Sat, Oct 18, 2014 at 6:34 PM, Dan Stromberg <drsali...@gmail.com> wrote: >>> Once the "nc" process actually write()s the data to its standard >>> output (i.e. desriptor 1, not the "stdout" FILE*) >> I'm not sure why you're excluding stdout, but even if nc is using >> filedes 1 instead of FILE * stdout, isn't it kind of irrelevant? > > On further reflection, isn't it stdio that does the varied buffering, > and filedes 1 that's always unbuffered? IOW, the OP might wish nc was > using 1, but it probably can't be given what they're seeing.
Yes. stdio does buffering. Writing to stdout stores data in a buffer; that data should eventually be written to descriptor 1, although perhaps not until immediately prior to termination. Which is probably the cause of the OP's problem. If it is, using a pseudo-tty would probably fix it. At startup, stdin and stdout are line-buffered if they are associated with a tty and fully-buffered otherwise (file, pipe, ...); stderr is unbuffered. At least, this is the case on Unix and Windows. The exact requirements of the C standard are: As initially opened, the standard error stream is not fully buffered; the standard input and standard output streams are fully buffered if and only if the stream can be determined not to refer to an interactive device. -- https://mail.python.org/mailman/listinfo/python-list