Jonsba/master (#100)

* Add a --unbuffered option for simulation. It disables buffering for stdout, stderr and files opened in write or append mode (TEXTIO).

Fixes #87 

* Some simplifications made on the previous commit. Documentation added for --unbuffered in Simulation_and_runtime.rst.

* Some more simplifications on unbuffered writes support for TEXTIO

* Fix a style issue failure reported by Travis-CI

4 files changed, 20 insertions, 0 deletions

diff --git a/src/grt/grt-files.adb b/src/grt/grt-files.adb
index a47381289..694572362 100644
--- a/src/grt/grt-files.adb
+++ b/src/grt/grt-files.adb
@@ -26,6 +26,7 @@ with Grt.Errors; use Grt.Errors;
 with Grt.Stdio; use Grt.Stdio;
 with Grt.C; use Grt.C;
 with Grt.Table;
+with Grt.Options;
 with System; use System;
 pragma Elaborate_All (Grt.Table);
 
@@ -195,6 +196,9 @@ package body Grt.Files is
          if F = NULL_Stream then
             return Name_Error;
          end if;
+         if Grt.Options.Unbuffered_Writes and Mode /= Read_Mode then
+            setbuf (F, NULL_voids);
+         end if;
       end if;
       Sig := Files_Table.Table (File).Signature;
       if Sig /= null then
diff --git a/src/grt/grt-options.adb b/src/grt/grt-options.adb
index 81fa962f0..943ff9626 100644
--- a/src/grt/grt-options.adb
+++ b/src/grt/grt-options.adb
@@ -25,6 +25,7 @@
 with Interfaces; use Interfaces;
 with Grt.Strings; use Grt.Strings;
 with Grt.Errors; use Grt.Errors;
+with Grt.Stdio; use Grt.Stdio;
 with Grt.Astdio;
 with Grt.Hooks;
 
@@ -477,6 +478,10 @@ package body Grt.Options is
             end if;
             Last_Generic_Override := Over;
          end;
+      elsif Option = "--unbuffered" then
+         Unbuffered_Writes := True;
+         setbuf (stdout, NULL_voids);
+         setbuf (stderr, NULL_voids);
       elsif not Grt.Hooks.Call_Option_Hooks (Option) then
          Error_C ("unknown option '");
          Error_C (Option);
diff --git a/src/grt/grt-options.ads b/src/grt/grt-options.ads
index 7233232d8..bd3721921 100644
--- a/src/grt/grt-options.ads
+++ b/src/grt/grt-options.ads
@@ -140,6 +140,10 @@ package Grt.Options is
    --  CPUs.
    Nbr_Threads : Natural := 1;
 
+   -- If true, writes are made without buffering on a file opened in write_mode
+   -- or append_mode (TEXTIO)
+   Unbuffered_Writes : Boolean := False;
+
    --  Set the time resolution.
    --  Only call this subprogram if you are allowed to set the time resolution.
    procedure Set_Time_Resolution (Res : Character);
diff --git a/src/grt/grt-stdio.ads b/src/grt/grt-stdio.ads
index 9084eab82..5e96d3535 100644
--- a/src/grt/grt-stdio.ads
+++ b/src/grt/grt-stdio.ads
@@ -38,6 +38,9 @@ package Grt.Stdio is
    --  NULL for a stream.
    NULL_Stream : constant FILEs;
 
+   -- NULL for a void pointer
+   NULL_voids : constant voids;
+
    --  Predefined streams.
    function stdout return FILEs;
    function stderr return FILEs;
@@ -47,6 +50,8 @@ package Grt.Stdio is
 
    function fopen (path: chars; mode : chars) return FILEs;
 
+   procedure setbuf (stream : FILEs; buffer : voids);
+
    function fwrite
      (buffer : voids; size : size_t; count : size_t; stream : FILEs)
      return size_t;
@@ -79,8 +84,10 @@ private
    --  of System).
    --  I am pretty sure the C definition of NULL is 0.
    NULL_Stream : constant FILEs := FILEs (System'To_Address (0));
+   NULL_voids : constant voids := voids (System'To_Address (0));
 
    pragma Import (C, fopen);
+   pragma Import (C, setbuf);
 
    pragma Import (C, fwrite);
    pragma Import (C, fread);