XEmacs 21.4.24 hangs when fd is pipe

Hi all, This pertains to 21.4.24 and earlier; I have not checked the 21.5 branch. There is a very rusty API called connec_to_file_descriptor() in process-unix.c. I am using it in an emodule. It works fine, from what I can tell. The problem I am encountering now, is that when the in fd is a pipe, and the pipe has less-than-internal-buffer-length it blocks on a subsequent read() system call. I am currently not sure how to "fix it". The culprit seems to be the if in Lstream_read(), inside the while loop. And the result is that it'll block on the read in filedesc_reader(). It's very wrong to adjust connect_to_file_descriptor() to make the resulting fd stream allow quits when read()ing. That just pushes the bug into user-visible space. Adding poll or select into the filedesc reader seems like the wrong solution, at first glance. Ideally, there should be a way to tell XEmacs to read() exactly once, but that also means getting rid of the while loop in Lstream_read() from what I can tell. Which may not be a good idea overall. Is there a way to fix this problem with minimal refactoring? Or am I cursed to have to fix all the internal buffering system in XEmacs to make connect_to_file_descriptor() usable with pipes? -- Johann I'm not from the internet, I just work there.