From 3feb864691cf855f0fcd0240731eb05206ec2254 Mon Sep 17 00:00:00 2001
From: John Ralls <jralls@ceridwen.us>
Date: Sun, 28 Apr 2019 16:59:51 -0700
Subject: [PATCH] Add an optionally-compiled diagnostic console on Windows.

---
 gnucash/gnucash-bin.c | 57 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 56 insertions(+), 1 deletion(-)

diff --git a/gnucash/gnucash-bin.c b/gnucash/gnucash-bin.c
index 3278d3ae61..659f17381f 100644
--- a/gnucash/gnucash-bin.c
+++ b/gnucash/gnucash-bin.c
@@ -58,11 +58,17 @@
 #include "guile-mappings.h"
 #ifdef __MINGW32__
 #include <Windows.h>
+#include <fcntl.h>
 #endif
 
 /* This static indicates the debugging module that this .o belongs to.  */
 static QofLogModule log_module = GNC_MOD_GUI;
 
+/* Change the following to have a console window attached to GnuCash
+ * for displaying stdout and stderr on Windows.
+ */
+#define __MSWIN_CONSOLE__ 0
+
 #ifdef HAVE_GETTEXT
 #  include <libintl.h>
 #  include <locale.h>
@@ -809,6 +815,53 @@ set_win32_thread_locale()
 }
 #endif
 
+/* Creates a console window on MSWindows to display stdout and stderr
+ * when __MSWIN_CONSOLE__ is defined at the top of the file.
+ *
+ * Useful for displaying the diagnostics printed before logging is
+ * started and if logging is redirected with --logto=stderr.
+ */
+static void
+redirect_stdout (void)
+{
+#ifdef __MINGW32__ && __MSWIN_CONSOLE__
+    static const WORD MAX_CONSOLE_LINES = 500;
+   int hConHandle;
+    long lStdHandle;
+    CONSOLE_SCREEN_BUFFER_INFO coninfo;
+    FILE *fp;
+
+    // allocate a console for this app
+    AllocConsole();
+
+    // set the screen buffer to be big enough to let us scroll text
+    GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &coninfo);
+    coninfo.dwSize.Y = MAX_CONSOLE_LINES;
+    SetConsoleScreenBufferSize(GetStdHandle(STD_OUTPUT_HANDLE), coninfo.dwSize);
+
+    // redirect unbuffered STDOUT to the console
+    lStdHandle = (long)GetStdHandle(STD_OUTPUT_HANDLE);
+    hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
+    fp = _fdopen( hConHandle, "w" );
+    *stdout = *fp;
+    setvbuf( stdout, NULL, _IONBF, 0 );
+
+    // redirect unbuffered STDIN to the console
+    lStdHandle = (long)GetStdHandle(STD_INPUT_HANDLE);
+    hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
+    fp = _fdopen( hConHandle, "r" );
+    *stdin = *fp;
+    setvbuf( stdin, NULL, _IONBF, 0 );
+
+    // redirect unbuffered STDERR to the console
+    lStdHandle = (long)GetStdHandle(STD_ERROR_HANDLE);
+    hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
+    fp = _fdopen( hConHandle, "w" );
+    *stderr = *fp;
+    setvbuf( stderr, NULL, _IONBF, 0 );
+#endif
+}
+
 int
 main(int argc, char ** argv)
 {
@@ -825,6 +878,7 @@ main(int argc, char ** argv)
         }
     }
 #endif
+    redirect_stdout ();
 
     /* This should be called before gettext is initialized
      * The user may have configured a different language via
@@ -846,7 +900,8 @@ main(int argc, char ** argv)
         g_setenv ("LC_ALL", "C", TRUE);
         setlocale (LC_ALL, "C");
       }
-#endif
+    else
+      printf ("Locale set to %s\n", sys_locale);
 #ifdef HAVE_GETTEXT
     {
         gchar *localedir = gnc_path_get_localedir();