sim: Persist calculator state on exit

The simulator already saves its state on EXIT_PGM (see src/dmcp/main.cc),
but only when a state-file path has previously been configured by the
user via the SETUP > State > Save menu. On a fresh install the path is
empty, so closing the window silently discards all settings (Beep mode,
display options, etc.) and stack contents.

Default the persisted state-file path to "state/<PROGRAM_NAME>.48S" on
first launch, so that exit reliably writes a state file and the next
launch reliably restores it.

Also honor STATE_IO_SILENT in state_load_callback. With the default path
set, the first launch (when no state file exists yet) was popping up a
"State load failed: No such file or directory" dialog; silent loads
should be silent on missing files too.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Signed-off-by: Alex Sergeev <alexander.sergeev@live.com>
Reviewed-by: Christophe de Dinechin <christophe@dinechin.org>

Author: 2 people

AUTHORS

@@ -21,6 +21,7 @@ This software was brought to you by the DB48X authors below
 - Mikael Djurfeldt <mikael@djurfeldt.com>
 - Pasquale Pigazzini <pasquale.pigazzini@gmail.com>
 - Wolf <wolfwings@wolfwings.us>
+- Alex Sergeev <alexander.sergeev@live.com>
 
 Copyright (c) 2022-2025, the DB48X authors
 

doc/0-Overview.md

@@ -843,7 +843,8 @@ Additional contributors to the project include (in order of appearance):
 * Ralf Ahlbrink (raprism@users.noreply.github.com)
 * Mikael Djurfeldt (mikael@djurfeldt.com)
 * Pasquale Pigazzini (pasquale.pigazzini@gmail.com)
-* Wolf <wolfwings@wolfwings.us>
+* Wolf (wolfwings@wolfwings.us)
+- Alex Sergeev (alexander.sergeev@live.com)
 
 The authors would like to acknowledge
 

help/db48x.md

@@ -785,7 +785,8 @@ Additional contributors to the project include (in order of appearance):
 * Ralf Ahlbrink (raprism@users.noreply.github.com)
 * Mikael Djurfeldt (mikael@djurfeldt.com)
 * Pasquale Pigazzini (pasquale.pigazzini@gmail.com)
-* Wolf <wolfwings@wolfwings.us>
+* Wolf (wolfwings@wolfwings.us)
+- Alex Sergeev (alexander.sergeev@live.com)
 
 The authors would like to acknowledge
 

help/db50x.md

@@ -794,7 +794,8 @@ Additional contributors to the project include (in order of appearance):
 * Ralf Ahlbrink (raprism@users.noreply.github.com)
 * Mikael Djurfeldt (mikael@djurfeldt.com)
 * Pasquale Pigazzini (pasquale.pigazzini@gmail.com)
-* Wolf <wolfwings@wolfwings.us>
+* Wolf (wolfwings@wolfwings.us)
+- Alex Sergeev (alexander.sergeev@live.com)
 
 The authors would like to acknowledge
 

sim/sim-window.cpp

@@ -106,6 +106,16 @@ MainWindow::MainWindow(QWidget *parent)
     QCoreApplication::setOrganizationName("DB48X");
     QCoreApplication::setApplicationName(PROGRAM_NAME);
 
+    // Default the persisted state file path on first run, so that the RPL
+    // engine's EXIT_PGM handler in main.cc actually writes a state file
+    // (it's a no-op when no path has been configured). The file lives
+    // under the app data dir; QDir::setCurrent() is already pointed there.
+    if (ui_read_setting("state", nullptr, 0) == 0)
+    {
+        QString defaultPath = QString("state/") + PROGRAM_NAME + ".48S";
+        ui_save_setting("state", defaultPath.toUtf8().constData());
+    }
+
     ui.setupUi(this);
 
     // Disable automatic layout management for manual control

src/dmcp/sysmenu.cc

@@ -395,8 +395,11 @@ static int state_load_callback(cstring path, cstring name, void *data)
         file prog(path, file::READING);
         if (!prog.valid())
         {
-            ui.draw_message("State load failed", prog.error(), name);
-            wait_for_key_press();
+            if (!is_silent)
+            {
+                ui.draw_message("State load failed", prog.error(), name);
+                wait_for_key_press();
+            }
             return 1;
         }