Add 'Allow Multiple Logins' soft-switch (WIP)

docs/changelog.md

@@ -6,6 +6,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## [Unreleased]
 
+### Work In Progress
+- **Allow Multiple Terminal Logins (experimental)** (2026-04-12)
+  - Added a persisted soft-switch `allow_multi_login` (bumped `SETTINGS_VERSION` to 107) which allows the same `Employee` to be logged into multiple terminals when enabled.
+  - Exposed a new Settings switch **Allow Multiple Logins** in the Settings UI (toggles and persists immediately).
+  - Login logic updated so `Terminal::LoginUser` and login UI checks consult `settings->allow_multi_login` before rejecting a login for a user already online.
+  - Files modified: `main/data/settings.hh`, `main/data/settings.cc`, `main/ui/labels.cc`, `zone/settings_zone.cc`, `main/hardware/terminal.cc`, `zone/login_zone.cc`.
+  - NOTE: This feature is experimental and a work in progress — bugs are likely. Use with caution and report any issues you encounter.
+
 ### Fixed
  - **Auto-Update vt_data: Prevent automatic updates when disabled (2026-04-09)**
    - Fixed unexpected vt_data downloads/updates triggered when restarting or shutting down from non-server displays even when "Auto-Update vt_data on Startup" is OFF.

main/data/settings.cc

@@ -1459,6 +1459,7 @@ Settings::Settings()
     expire_message3.Set("541-515-5913");
     expire_message4.Set("");
     allow_multi_coupons = 0;
+    allow_multi_login = 0;
     cc_print_custinfo       = 0;
 
     for (i = 0; i < MAX_CDU_LINES; i++)
@@ -2132,6 +2133,8 @@ int Settings::Load(const char* file)
         df.Read(report_start_midnight);
     if (version >= 79)
         df.Read(allow_multi_coupons);
+    if (version >= 107)
+        df.Read(allow_multi_login);
     if (version >= 82)
         df.Read(allow_iconify);
     if (version >= 96)
@@ -2527,6 +2530,7 @@ int Settings::Save()
     df.Write(cc_bar_mode);
     df.Write(report_start_midnight);
     df.Write(allow_multi_coupons);
+    df.Write(allow_multi_login);
     df.Write(allow_iconify);
     df.Write(use_embossed_text);
     df.Write(use_text_antialiasing);

main/data/settings.hh

@@ -30,7 +30,7 @@
 // NOTE:  WHEN UPDATING SETTINGS DO NOT FORGET that you may also
 // need to update archive.hh and archive.cc for settings which
 // should be maintained historically.
-constexpr int SETTINGS_VERSION = 106;  // READ ABOVE
+constexpr int SETTINGS_VERSION = 107;  // READ ABOVE
 
 
 /**** Definitions & Data ****/
@@ -166,6 +166,7 @@ enum DrawerMode : std::uint8_t {
 #define SWITCH_F3_F4_RECORDING   32 // whether to enable F3/F4 recording/replay feature
 #define SWITCH_AUTO_UPDATE_VT_DATA 33 // whether to automatically download vt_data on startup
 #define SWITCH_BUTTON_IMAGES       34 // toggle showing images on buttons
+#define SWITCH_ALLOW_MULTI_LOGIN   35 // allow same user to login on multiple terminals
 
 #define MOD_SEPARATE_NL           1 // New line
 #define MOD_SEPARATE_CM           2 // Comma
@@ -624,6 +625,9 @@ public:
     int split_check_view;        // default to item or seat list for SplitCheckZone?
     int allow_multi_coupons;
 
+    // Allow same employee to be logged into multiple terminals when set
+    int allow_multi_login;
+
     // allow_user_select is primarily for ExpenseZone, but may be used elsewhere
     int allow_user_select;       // yes == user selection, no == force term->user
 

main/hardware/terminal.cc

@@ -2043,7 +2043,16 @@ int Terminal::LoginUser(Employee *employee, bool home_page)
     if (AllowLogins == 0)
         return 1;
 
-    if (employee == nullptr || (user != employee && parent->IsUserOnline(employee)))
+    if (employee == nullptr)
+        return 1;
+
+    // Check whether multiple logins are allowed via settings
+    Settings *s = GetSettings();
+    int allow_multi = 0;
+    if (s)
+        allow_multi = s->allow_multi_login;
+
+    if (user != employee && parent != nullptr && parent->IsUserOnline(employee) && !allow_multi)
         return 1;  // User already online on another terminal
 
     if (user != nullptr && user != employee)

main/ui/labels.cc

@@ -448,6 +448,7 @@ const genericChar* SwitchName[] = {
     "24 Hour Mode", "Item Targeting",
     "Expand Goodwill Adjustments", "Monetary Symbol",
     "Show Modifiers", "Allow Multiple Coupons",
+    "Allow Multiple Logins",
     "Print All Modifiers on Receipt", "Auto Print Drawer Report",
     "Balance Automatic Coupons", "Enable F3/F4 Recording/Replay", "Auto-Update vt_data on Startup",
     "Show Button Images", nullptr};
@@ -462,6 +463,7 @@ int SwitchValue[] = {
     SWITCH_MEASUREMENTS, SWITCH_AUTHORIZE_METHOD, SWITCH_24HOURS,
     SWITCH_ITEM_TARGET, SWITCH_GOODWILL, SWITCH_MONEY_SYMBOL,
     SWITCH_SHOW_MODIFIERS, SWITCH_ALLOW_MULT_COUPON,
+    SWITCH_ALLOW_MULTI_LOGIN,
     SWITCH_RECEIPT_ALL_MODS, SWITCH_DRAWER_PRINT,
     SWITCH_BALANCE_AUTO_CPNS, SWITCH_F3_F4_RECORDING, SWITCH_AUTO_UPDATE_VT_DATA,
     SWITCH_BUTTON_IMAGES, -1};

zone/login_zone.cc

@@ -417,7 +417,7 @@ int LoginZone::ClockOn(Terminal *term, int job_no)
     }
     else
     {
-        if (term->IsUserOnline(employee) && term->user != employee)
+        if (term->IsUserOnline(employee) && term->user != employee && !settings->allow_multi_login)
         {
             state = STATE_ON_ANOTHER_TERM;
             Draw(term, 0);
@@ -494,7 +494,7 @@ int LoginZone::ClockOff(Terminal *term)
             state = STATE_NOT_ON_CLOCK;
         else if (sys->CountOpenChecks(employee) > 0)
             state = STATE_OPEN_CHECK;
-        else if (term->IsUserOnline(employee) && term->user != employee)
+        else if (term->IsUserOnline(employee) && term->user != employee && !sys->settings.allow_multi_login)
             state = STATE_ON_ANOTHER_TERM;
         else if (term->NeedDrawerBalanced(employee))
             state = STATE_NEED_BALANCE;
@@ -634,7 +634,7 @@ int LoginZone::Start(Terminal *term, short expedite)
 
         return 0;
     }
-    else if (term->IsUserOnline(employee))
+    else if (term->IsUserOnline(employee) && !settings->allow_multi_login)
     {
         // user already logged into another term
         state = STATE_ON_ANOTHER_TERM;

zone/settings_zone.cc

@@ -271,6 +271,9 @@ RenderResult SwitchZone::Render(Terminal *term, int update_flag)
     case SWITCH_ALLOW_MULT_COUPON:
         onoff = settings->allow_multi_coupons;
         break;
+    case SWITCH_ALLOW_MULTI_LOGIN:
+        onoff = settings->allow_multi_login;
+        break;
     case SWITCH_RECEIPT_ALL_MODS:
         onoff = settings->receipt_all_modifiers;
         break;
@@ -595,6 +598,11 @@ SignalResult SwitchZone::Touch(Terminal *term, int /*tx*/, int /*ty*/)
     case SWITCH_ALLOW_MULT_COUPON:
         settings->allow_multi_coupons ^= 1;
         break;
+    case SWITCH_ALLOW_MULTI_LOGIN:
+        settings->allow_multi_login ^= 1;
+        // Persist immediately so change survives restarts
+        settings->Save();
+        break;
     case SWITCH_RECEIPT_ALL_MODS:
         settings->receipt_all_modifiers ^= 1;
         break;