How to resolve the algorithm Execute a system command step by step in the OCaml programming language

Published on 12 May 2024 09:40 PM

How to resolve the algorithm Execute a system command step by step in the OCaml programming language

Table of Contents

Problem Statement

Run either the   ls   system command   (dir   on Windows),   or the   pause   system command.

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Execute a system command step by step in the OCaml programming language

Source code in the ocaml programming language

Sys.command "ls"


#load "unix.cma"

let syscall cmd =
  let ic, oc = Unix.open_process cmd in
  let buf = Buffer.create 16 in
  (try
     while true do
       Buffer.add_channel buf ic 1
     done
   with End_of_file -> ());
  let _ = Unix.close_process (ic, oc) in
  (Buffer.contents buf)

let listing = syscall "ls" ;;


let check_exit_status = function
  | Unix.WEXITED 0 -> ()
  | Unix.WEXITED r -> Printf.eprintf "warning: the process terminated with exit code (%d)\n%!" r
  | Unix.WSIGNALED n -> Printf.eprintf "warning: the process was killed by a signal (number: %d)\n%!" n
  | Unix.WSTOPPED n -> Printf.eprintf "warning: the process was stopped by a signal (number: %d)\n%!" n
;;

let syscall ?(env=[| |]) cmd =
  let ic, oc, ec = Unix.open_process_full cmd env in
  let buf1 = Buffer.create 96
  and buf2 = Buffer.create 48 in
  (try
     while true do Buffer.add_channel buf1 ic 1 done
   with End_of_file -> ());
  (try
     while true do Buffer.add_channel buf2 ec 1 done
   with End_of_file -> ());
  let exit_status = Unix.close_process_full (ic, oc, ec) in
  check_exit_status exit_status;
  (Buffer.contents buf1,
   Buffer.contents buf2)


  

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