On my Unix-based Mac OS, I have a command mdls -name kMDItemNumberOfPages -raw to compute the number of pages inside a pdf. To get that integer inside an Ocaml program, I proceed as follows : I create a temporary file with Sys.command "touch temp.txt" Store the result in the temporary file with S…

If you use the Unix library, you can directly read the stdout of the program via Unix.open_process_in .

[image] dbuenzli: You can directly read the stdout of the program via Unix.open_process_in . If I understand correctly, let my_channel=Unix.open_process_in "some_cmd" ;; stores the result of some_cmd in a value my_channel of type in_channel. How do I retrieve the result stored in my_channel af…

[image] vrotaru: Get the length of input_channel. You can’t, the length of a standard output is unknown. [image] jonathandoyle: stores the result of some_cmd in a value my_channel of type in_channel . How do I retrieve the result stored in my_channel after that ? It does not store the…

[image] dbuenzli: You can directly read the stdout of the program via Unix.open_process_in . I tried it this morning (yesterday I just read the linked manual sections) and surprisingly it doesn’t work at all in my case. My call to Unix.open_process_in not only raises a Unix.Unix_error(Unix.EIN…

I’m not using utop so I can’t exactly tell you. But that’s precisely one of the reasons I don’t, its implementation fiddles with and embeds too much in your environment (notably lwt). So I prefer to stick to ocaml in general (with rlwrap or down ).

This is my “screenshot”. You may want to give the new version a try. ──┬─────────────────────────────────────────────────────────────┬── │ Welcome to utop version 2.6.0 (using OCaml version 4.08.1)! │ └─────────────────────────────────────────────────────────────┘ Findlib has been successfu…

Retrieving the integer result of a Unix command inside OCaml code

Learning

vrotaru May 30, 2020, 10:29pm 4

Get the length of input_channel. (There a function for that in Stdlib) Then use

really_input_string in len |> int_of_string

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Retrieving the integer result of a Unix command inside OCaml code

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