diff -r 078c760620d7 -r 6dbc61e3dd65 targets/Win32/plc_Win32_main.c
--- a/targets/Win32/plc_Win32_main.c	Sat Nov 19 22:20:19 2016 +0100
+++ b/targets/Win32/plc_Win32_main.c	Sat Nov 19 23:42:49 2016 +0100
@@ -84,7 +84,7 @@
     if (debug_sem == NULL)
     {
         printf("startPLC CreateSemaphore debug_sem error: %d\n", GetLastError());
-        return;
+        return 1;
     }
 
     debug_wait_sem = CreateSemaphore(
@@ -96,7 +96,7 @@
     if (debug_wait_sem == NULL)
     {
         printf("startPLC CreateSemaphore debug_wait_sem error: %d\n", GetLastError());
-        return;
+        return 1;
     }
 
     python_sem = CreateSemaphore(
@@ -108,7 +108,7 @@
     if (python_sem == NULL)
     {
         printf("startPLC CreateSemaphore python_sem error: %d\n", GetLastError());
-        return;
+        return 1;
     }
     python_wait_sem = CreateSemaphore(
                             NULL,           // default security attributes
@@ -120,7 +120,7 @@
     if (python_wait_sem == NULL)
     {
         printf("startPLC CreateSemaphore python_wait_sem error: %d\n", GetLastError());
-        return;
+        return 1;
     }