Detect if we were double-clicked.

Because we are compiled as a console subsystem application, if the user
double-clicks the executable it will pop up a new console window.  Then,
since no arguments were passed, we will dump a usage message which the
user won't have time to read, and exit.

We now detect this situation and redirect the usage message to a popup.

There are three likely cases to handle.

If we are running in a service context there won't be a console window.
GetConsoleWindow() will return a null handle.

If were launched from a command window, the process ID owning the
console handle will be different from as our process ID.

If the process IDs are the same, we were started with a new console.  We
call FreeConsole() to close it and subsequently direct the usage message
to a message box.

diff --git a/event.cpp b/event.cpp
index 1313351..4af50a8 100644 (file)
--- a/event.cpp
+++ b/event.cpp
@@ -80,12 +80,12 @@ int popup_message(unsigned int type, unsigned long id, ...) {
     return MessageBox(0, _T("The message which was supposed to go here is missing!"), NSSM, MB_OK | MB_ICONEXCLAMATION);\r
   }\r
 \r
-  TCHAR blurb[512];\r
+  TCHAR blurb[1024];\r
   va_start(arg, id);\r
   if (_vsntprintf_s(blurb, _countof(blurb), _TRUNCATE, format, arg) < 0) {\r
     va_end(arg);\r
     LocalFree(format);\r
-    return MessageBox(0, _T("the message which was supposed to go here is too big!"), NSSM, MB_OK | MB_ICONEXCLAMATION);\r
+    return MessageBox(0, _T("The message which was supposed to go here is too big!"), NSSM, MB_OK | MB_ICONEXCLAMATION);\r
   }\r
   va_end(arg);\r
 \r

diff --git a/nssm.cpp b/nssm.cpp
index 7c95611..7e1e7ce 100644 (file)
--- a/nssm.cpp
+++ b/nssm.cpp
@@ -24,7 +24,8 @@ void strip_basename(TCHAR *buffer) {
 \r
 /* How to use me correctly */\r
 int usage(int ret) {\r
-  print_message(stderr, NSSM_MESSAGE_USAGE, NSSM_VERSION, NSSM_DATE);\r
+  if (GetConsoleWindow()) print_message(stderr, NSSM_MESSAGE_USAGE, NSSM_VERSION, NSSM_DATE);\r
+  else popup_message(MB_OK, NSSM_MESSAGE_USAGE, NSSM_VERSION, NSSM_DATE);\r
   return(ret);\r
 }\r
 \r
@@ -39,7 +40,29 @@ void check_admin() {
   FreeSid(AdministratorsGroup);\r
 }\r
 \r
+/* See if we were launched from a console window. */\r
+static void check_console() {\r
+  /* If we're running in a service context there will be no console window. */\r
+  HWND console = GetConsoleWindow();\r
+  if (! console) return;\r
+\r
+  unsigned long pid;\r
+  if (! GetWindowThreadProcessId(console, &pid)) return;\r
+\r
+  /*\r
+    If the process associated with the console window handle is the same as\r
+    this process, we were not launched from an existing console.  The user\r
+    probably double-clicked our executable.\r
+  */\r
+  if (GetCurrentProcessId() != pid) return;\r
+\r
+  /* We close our new console so that subsequent messages appear in a popup. */\r
+  FreeConsole();\r
+}\r
+\r
 int _tmain(int argc, TCHAR **argv) {\r
+  check_console();\r
+\r
   /* Remember if we are admin */\r
   check_admin();\r
 \r