diff --git a/lib/boinc_win.h b/lib/boinc_win.h
index 20713d0520..882f27a8ac 100644
--- a/lib/boinc_win.h
+++ b/lib/boinc_win.h
@@ -80,7 +80,7 @@
 #include <sys/types.h>
 #include <fcntl.h>
 
-#ifdef __cplusplus
+#if defined(__cplusplus)
 #include <cassert>
 #include <cctype>
 #include <cerrno>
@@ -104,9 +104,10 @@
 #include <time.h>
 #endif
 
-
 // C++ headers
-#ifdef __cplusplus
+//
+
+#if defined(__cplusplus)
 #include <algorithm>
 #include <string>
 #include <iostream>
diff --git a/lib/diagnostics.h b/lib/diagnostics.h
index 1c7df59b59..0ebcd6d964 100644
--- a/lib/diagnostics.h
+++ b/lib/diagnostics.h
@@ -126,11 +126,13 @@ extern void boinc_set_signal_handler_force(int sig, void(*handler)(int));
 #ifdef __cplusplus
 extern "C" {
 #endif
+
 extern int boinc_init_diagnostics(int flags);
-extern int boinc_finish_diag(void);
-extern int boinc_install_signal_handlers(void);
+extern int boinc_finish_diag();
+extern int boinc_install_signal_handlers();
 
 #ifdef __cplusplus
 }
 #endif
+
 #endif
diff --git a/lib/filesys.h b/lib/filesys.h
index f5099f9c30..825c698ff1 100755
--- a/lib/filesys.h
+++ b/lib/filesys.h
@@ -39,11 +39,12 @@
 
 #ifdef _WIN32
 
-typedef struct DIR_DESC {
+typedef struct _DIR_DESC {
     char path[256];
     bool first;
     void* handle;
-};
+} DIR_DESC;
+
 typedef DIR_DESC *DIRREF;
 #define PATH_SEPARATOR "\\"