On Tue, Mar 19, 2002 at 02:54:24PM -0800, Thomas Bushnell, BSG wrote: > I'm baffled. If it's a plain pipe, then you simply close the end > you're writing on, and the reader gets EOF. > > I assumed the implementation used socketpairs, where closing your > writing half would prevent you from also reading on it.
The implementation is using the Hurd's IO interface. It seems I was not clear enough in my original mail. The translator creates a pipe to the forked program, and translates io_read into a pipe read and io_write into a pipe write. The translator forks for every open(). Now, suppose you have a program like wc that collects data and returns a summary of that data. It will read from stdin until it gets EOF, and then print from stdout. But if I use the above translator, I have only one filedescriptor, and I cannot simply close it if I want to read back the summary of wc. So how do I inform the translator that it should close the pipe the forked program reads from (it can easily use two pipes instead one bidirectional one, but the program holding a port to the translator can not easily get two ports, one for the reads and one for the writes). Thanks Marcus _______________________________________________ Bug-hurd mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/bug-hurd
