Haskell Compiled IO-Action order and Flushing -

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• io happens out of order when using getline , putstr 3 answers

i'm encountering strange behaviour io, within compiled haskell code. here's what's going on:

-- myscript.hs main =     putstr "enter name: "     <- getline     putstrln (a ++ " - that's nice name!") 

i run in ghci calling main , works 1 expect, first printing enter name: , doing whatever it's afterwards. however, when compile ghc (with , without --make), first prompts line, , then prints @ once, this:

$ ./myscript jimmy johnson enter name: jimmy johnson - that's nice name! 

to clarify, want occur in following sequence:

$ ./myfixedscript enter name: jimmy johnson jimmy johnson - that's nice name! 

could explain why happens is, , how sequence io way expect to.

note i've tried changing first line of do statement _ <- putstr "enter name: ", still doesn't work.

the io actions happening in correct order, problem lies in how input , output pipes work. string "enter name: " written output buffer putstr before getline, buffer hasn't been flushed. adding hflush stdout after putstr flush buffer.

import system.io  -- myscript.hs main =     putstr "enter name: "     hflush stdout     <- getline     putstrln (a ++ " - that's nice name!")