5 files changed, 105 insertions, 14 deletions
diff --git a/src/grt/grt-c.ads b/src/grt/grt-c.ads
index 64b43127a..e2a66c705 100644
--- a/src/grt/grt-c.ads
+++ b/src/grt/grt-c.ads
@@ -34,6 +34,8 @@ package Grt.C is
 
    --  Type size_t.
    type size_t is mod 2 ** Standard'Address_Size;
+   type ssize_t is range
+     -2 ** (Standard'Address_Size - 1) .. 2 ** (Standard'Address_Size - 1) - 1;
 
    --  Type int.  It is an alias on Integer for simplicity.
    subtype int is Integer;
diff --git a/src/grt/grt-readline.ads b/src/grt/grt-readline.ads
index 5eb1b5c7f..12739f07c 100644
--- a/src/grt/grt-readline.ads
+++ b/src/grt/grt-readline.ads
@@ -1,14 +1,2 @@
---  Although being part of GRT, the readline binding should be independent of
---  it (for easier reuse).
-
-with Grt.Types; use Grt.Types;
-
-package Grt.Readline is
-   function Readline (Prompt : Ghdl_C_String) return Ghdl_C_String;
-   pragma Import (C, Readline);
-
-   procedure Add_History (Line : Ghdl_C_String);
-   pragma Import (C, Add_History);
-
-   pragma Linker_Options ("-lreadline");
-end Grt.Readline;
+with Grt.Readline_Gnu;
+package Grt.Readline renames Grt.Readline_Gnu;
diff --git a/src/grt/grt-readline_gnu.ads b/src/grt/grt-readline_gnu.ads
new file mode 100644
index 000000000..4d0fc5473
--- /dev/null
+++ b/src/grt/grt-readline_gnu.ads
@@ -0,0 +1,12 @@
+--  Binding to GNU readline
+with Grt.Types; use Grt.Types;
+
+package Grt.Readline_Gnu is
+   function Readline (Prompt : Ghdl_C_String) return Ghdl_C_String;
+   pragma Import (C, Readline);
+
+   procedure Add_History (Line : Ghdl_C_String);
+   pragma Import (C, Add_History);
+
+   pragma Linker_Options ("-lreadline");
+end Grt.Readline_Gnu;
diff --git a/src/grt/grt-readline_none.adb b/src/grt/grt-readline_none.adb
new file mode 100644
index 000000000..cbcf35b19
--- /dev/null
+++ b/src/grt/grt-readline_none.adb
@@ -0,0 +1,60 @@
+--  GHDL Run Time (GRT) - Stupid emulation of readline using stdio
+--  Copyright (C) 2022 Tristan Gingold
+--
+--  This program is free software: you can redistribute it and/or modify
+--  it under the terms of the GNU General Public License as published by
+--  the Free Software Foundation, either version 2 of the License, or
+--  (at your option) any later version.
+--
+--  This program is distributed in the hope that it will be useful,
+--  but WITHOUT ANY WARRANTY; without even the implied warranty of
+--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--  GNU General Public License for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with this program.  If not, see <gnu.org/licenses>.
+--
+--  As a special exception, if other files instantiate generics from this
+--  unit, or you link this unit with other files to produce an executable,
+--  this unit does not by itself cause the resulting executable to be
+--  covered by the GNU General Public License. This exception does not
+--  however invalidate any other reasons why the executable file might be
+--  covered by the GNU Public License.
+with System; use System;
+with Grt.C; use Grt.C;
+with Grt.Stdio; use Grt.Stdio;
+
+package body Grt.Readline_None is
+   function getline (Linep : Address; Linecapp : Address; Stream : FILEs)
+                    return ssize_t;
+   pragma Import (C, getline);
+
+   function Readline (Prompt : Ghdl_C_String) return Ghdl_C_String
+   is
+      Len : ssize_t;
+      Linep : Ghdl_C_String;
+      Linecapp : size_t;
+      T : int;
+   begin
+      T := fputs (To_Address (Prompt), stdout);
+      pragma Unreferenced (T);
+
+      Linep := null;
+      Linecapp := 0;
+      Len := getline (Linep'Address, Linecapp'Address, stdin);
+      if Len <= 0 then
+         free (Linep);
+         return null;
+      end if;
+      --  Remove end of line.
+      if Linep (Natural (Len)) = ASCII.LF then
+         Linep (Natural (Len)) := ASCII.NUL;
+      end if;
+      return Linep;
+   end Readline;
+
+   procedure Add_History (Line : Ghdl_C_String) is
+   begin
+      null;
+   end Add_History;
+end Grt.Readline_None;
diff --git a/src/grt/grt-readline_none.ads b/src/grt/grt-readline_none.ads
new file mode 100644
index 000000000..597e8f6ea
--- /dev/null
+++ b/src/grt/grt-readline_none.ads
@@ -0,0 +1,29 @@
+--  GHDL Run Time (GRT) - Stupid emulation of readline using stdio
+--  Copyright (C) 2022 Tristan Gingold
+--
+--  This program is free software: you can redistribute it and/or modify
+--  it under the terms of the GNU General Public License as published by
+--  the Free Software Foundation, either version 2 of the License, or
+--  (at your option) any later version.
+--
+--  This program is distributed in the hope that it will be useful,
+--  but WITHOUT ANY WARRANTY; without even the implied warranty of
+--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--  GNU General Public License for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with this program.  If not, see <gnu.org/licenses>.
+--
+--  As a special exception, if other files instantiate generics from this
+--  unit, or you link this unit with other files to produce an executable,
+--  this unit does not by itself cause the resulting executable to be
+--  covered by the GNU General Public License. This exception does not
+--  however invalidate any other reasons why the executable file might be
+--  covered by the GNU Public License.
+with Grt.Types; use Grt.Types;
+
+package Grt.Readline_None is
+   function Readline (Prompt : Ghdl_C_String) return Ghdl_C_String;
+
+   procedure Add_History (Line : Ghdl_C_String);
+end Grt.Readline_None;