I once tried to fork out a pipelined process into the background that
I could pipe input to and then read the output from (hopefully without
using files). I never quite got it working (the I/O wouldn't block
when there was no data), but that may be my poor shell programming
skills. I'm thinking something like:
( exec sed -e 's/^dirname:<dirname-expr>' \
-e 's/^uppercase:<uppercase-expr>' \
... \
-e '/^quit$/ q' <<sed_in_fd> ><sed_out_fd> ) &
echo "dirname:$0" >$sed_in_fd
read basename <$sed_out_fd
I know the above doesn't work, but could it be done in some other,
hopefully portable, way? Wouldn't it speed up configure by a lot if
we could apply it to the right sub-tasks?
I was even thinking the "resident" sub-process could be a shell that
looped over a read+switch/case expression to emulate functions, but as
I said, I never got the I/O quite working.
Lars J
