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[Caml-list] process conundrum
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Date: -- (:)
From: David Fox <david@l...>
Subject: [Caml-list] process conundrum
Suppose I open a process to reverse the lines of a file like so:

# let readable, writable = 
  Unix.open_process "cat -n | sort -n -r | sed 's:^[ 0-9]*[^ 0-9]::'";;

Then I write a few lines to it:

# output_string writable "a\n";;
# output_string writable "b\n";;
# output_string writable "c\n";;

Now I close the write end to cause an EOF, so the output arrives on readable:

# close_out writable;;
# input_line readable;;
- : string = "c"
# input_line readable;;
- : string = "b"
# input_line readable;;
- : string = "a"
# input_line readable;;
Exception: End_of_file.

How do I cleanly terminate the process?

# Unix.close_process (readable, writable);;
Exception: Sys_error "Bad file descriptor".
# 
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