Reworded error message displayed when cxbxr fails to launch an xbe

src/common/win32/InlineFunc.cpp

@@ -47,13 +47,13 @@ bool CxbxIsElevated() {
 	return fRet;
 }
 
-bool CxbxExec(bool useDebugger, HANDLE* hProcess, bool requestHandleProcess) {
+std::optional<std::string> CxbxExec(bool useDebugger, HANDLE* hProcess, bool requestHandleProcess) {
 
 	STARTUPINFO startupInfo = { 0 };
 	PROCESS_INFORMATION processInfo = { 0 };
 	std::string szProcArgsBuffer;
 	if (!cli_config::GenCMD(szProcArgsBuffer)) {
-		return false;
+		return std::make_optional<std::string>("Failed to retrieve the command line arguments to launch the new emulation process");
 	}
 
 	// TODO: Set a configuration variable for this. For now it will be within the same folder as Cxbx.exe
@@ -69,7 +69,7 @@ bool CxbxExec(bool useDebugger, HANDLE* hProcess, bool requestHandleProcess) {
 		cpu load cycles to get the task done.
 	*/
 	if (CreateProcess(nullptr, const_cast<LPSTR>(szProcArgsBuffer.c_str()), nullptr, nullptr, false, 0, nullptr, nullptr, &startupInfo, &processInfo) == 0) {
-		return 0;
+		return std::make_optional<std::string>("Failed to create the new emulation process (another instance of cxbxr is already running?)");
 	}
 	CloseHandle(processInfo.hThread);
 
@@ -80,7 +80,7 @@ bool CxbxExec(bool useDebugger, HANDLE* hProcess, bool requestHandleProcess) {
 		CloseHandle(processInfo.hProcess);
 	}
 
-	return 1;
+	return std::nullopt;
 }
 
 #endif

src/core/kernel/init/CxbxKrnl.h

@@ -30,6 +30,7 @@
 #include "common/ReserveAddressRanges.h"
 #include "common\xbe\Xbe.h"
 #include "Logging.h"
+#include <optional>
 
 #include <windows.h>
 #include <multimon.h>
@@ -188,8 +189,6 @@ void CxbxInitFilePaths();
 bool CxbxLockFilePath();
 void CxbxUnlockFilePath();
 
-bool CxbxExec(bool useDebugger, HANDLE* hProcess, bool requestHandleProcess);
-
 bool CxbxIsElevated();
 
 /*! kernel thunk table */
@@ -229,6 +228,8 @@ extern char szFilePath_Xbe[xbox::max_path*2];
 }
 #endif
 
+std::optional<std::string> CxbxExec(bool useDebugger, HANDLE *hProcess, bool requestHandleProcess);
+
 // Returns the last Win32 error, in string format. Returns an empty string if there is no error.
 extern std::string CxbxGetLastErrorString(char * lpszFunction);
 

src/core/kernel/support/EmuFile.cpp

@@ -1330,9 +1330,9 @@ void CxbxLaunchNewXbe(const std::string& XbePath) {
 	}
 	else
 	{
-		if (!CxbxExec(false, nullptr, false))
+		if (const auto &err = CxbxExec(false, nullptr, false))
 		{
-			CxbxKrnlCleanup("Could not launch %s", XbePath.c_str());
+			CxbxKrnlCleanup("Could not launch %s\n\nThe reason was: %s", XbePath.c_str(), err->c_str());
 		}
 	}
 

src/gui/WndMain.cpp

@@ -2261,7 +2261,7 @@ void WndMain::StartEmulation(HWND hwndParent, DebuggerState LocalDebuggerState /
             // Check then close existing debugger monitor.
             DebuggerMonitorClose();
 
-            if (!CxbxExec(true, &m_hDebuggerProc, true)) {
+            if (CxbxExec(true, &m_hDebuggerProc, true)) {
                 PopupError(m_hwnd, "Failed to start emulation with the debugger.\n\nYou will need to build CxbxDebugger manually.");
 
                 printf("WndMain: %s debugger shell failed.\n", m_Xbe->m_szAsciiTitle);
@@ -2274,8 +2274,8 @@ void WndMain::StartEmulation(HWND hwndParent, DebuggerState LocalDebuggerState /
         }
         else {
 
-            if (!CxbxExec(false, nullptr, false)) {
-                PopupError(m_hwnd, "Emulation failed.\n\n If this message repeats, the Xbe is not supported.");
+            if (const auto &err = CxbxExec(false, nullptr, false)) {
+                PopupError(m_hwnd, err->c_str());
 
                 printf("WndMain: %s shell failed.\n", m_Xbe->m_szAsciiTitle);
             }