read keys from windows konsole

[Matze]

Hello,
how can I read characters in FPC from Windows console with e.g.:
echo j | fpc.exe
If I start my program this way, it does not react to keyboard input (readkey / keypressed) any more.
What am I doing wrong?
Keys that were pressed before program started are also not read.

---
Lazarus 1.8.2
FPC 3.0.4
Windows 10

[Bart]

I assume this is a console program
I would assume reading from input should work, something like (untested):

Code: Pascal  [Select][+][-]

1.   while not eof(input) do readln(somestring);

I did have some program that I coud pipe input into suing such a construct.

IIRC then this does not work if the program uses the crt unit, nor if the program has no console (Windows GUI app).

Bart

[Thaddy]

no need for crt.
just read/readln from system.

[Matze]

no, if i type
echo j | myprogram.exe
read / readln returns nothing and if then pressing a key is not recognized

[Bart]

This works for me:

Code: Pascal  [Select][+][-]

1. program test;
2. {$ifdef fpc}
3. {$mode objfpc}
4. {.$mode delphi}
5. {$h-}
6. //{$mode delphi}
7. //{$modeswitch advancedrecords}
8. {$endif}
9. {$apptype console}
10. //{$R+}
11.  
12. var
13.   S: String;
14.  
15. begin
16.   while not EOF do
17.   begin
18.     readln(S);
19.     writeln('S=',S);
20.   end;
21. end.

Code: [Select]

C:\Users\Bart\LazarusProjecten\ConsoleProjecten>test < test.pas
S=program test;
S={$ifdef fpc}
S={$mode objfpc}
S={.$mode delphi}
S={$h-}
S=//{$mode delphi}
S=//{$modeswitch advancedrecords}
S={$endif}
S={$apptype console}
S=//{$R+}
S=
S=var
S=  S: String;
S=
S=begin
S=  while not EOF do
S=  begin
S=    readln(S);
S=    writeln('S=',S);
S=  end;
S=end.

C:\Users\Bart\LazarusProjecten\ConsoleProjecten>echo foobar | test
S=foobar
And this stops working as soon as you use the crt unit.
And AFAIK this also was the case in the good old TP days.

Bart

[TRon]

And AFAIK this also was the case in the good old TP days.

That is correct Bart.

[Matze]

ok
is there any way to get this work with unit crt?

[marcov]

Try

Code: Pascal  [Select][+][-]

1. reset(input,'');

as first statement in your program. Note that only preserves the output functionality, iskeypressed/readkey can't be used anymore.