diff --git a/api/boincdiag.cpp b/api/boincdiag.cpp
index 8e0f70f795..da3049540f 100644
--- a/api/boincdiag.cpp
+++ b/api/boincdiag.cpp
@@ -37,7 +37,7 @@
 
 
 // Well if we are not using the MFC/ATL frameworks, then we are using the CRT.
-#else __AFXWIN_H__
+#else // __AFXWIN_H__
 
 #include <windows.h>
 #include <stdio.h>
@@ -63,7 +63,7 @@ void boinc_trace(const char *pszFormat, ...)
 	_CrtDbgReport(_CRT_WARN, NULL, NULL, NULL, "%s", szBuffer);
 }
 
-#endif _DEBUG
+#endif // _DEBUG
 
 
 //
@@ -152,6 +152,6 @@ int boinc_diag_cleanup() {
 }
 
 
-#endif __AFXWIN_H__
+#endif // __AFXWIN_H__
 
-#endif _WIN32
+#endif // _WIN32
diff --git a/api/boincdiag.h b/api/boincdiag.h
index f4c0a3e547..d288449f63 100644
--- a/api/boincdiag.h
+++ b/api/boincdiag.h
@@ -66,7 +66,7 @@ void	boinc_trace(const char *pszFormat, ...);
 
 
 // Well if we are not using the MFC/ATL frameworks, then we are using the CRT.
-#else __AFXWIN_H__
+#else // __AFXWIN_H__
 
 
 //
@@ -84,16 +84,16 @@ void	boinc_trace(const char *pszFormat, ...);
 #define BOINCASSERT(expr)	_ASSERT_BASE((expr), #expr)
 #define BOINCTRACE			boinc_trace
 
-#else _DEBUG
+#else // _DEBUG
 
 #define BOINCASSERT(expr)	((void)0)
 #define BOINCTRACE			((void)0)
 
-#endif _DEBUG
+#endif // _DEBUG
 
-#endif __AFXWIN_H__
+#endif // __AFXWIN_H__
 
-#endif _WIN32
+#endif // _WIN32
 
 
 
@@ -118,4 +118,4 @@ void	boinc_trace(const char *pszFormat, ...);
 #endif
 
 
-#endif _BOINC_DIAGNOSTICS_
\ No newline at end of file
+#endif //_BOINC_DIAGNOSTICS_
\ No newline at end of file
diff --git a/checkin_notes b/checkin_notes
index 5e22f8787b..e68254d8b3 100755
--- a/checkin_notes
+++ b/checkin_notes
@@ -9667,3 +9667,9 @@ Rom    Feb 2 2004
     api/
         boincdiag.cpp,h (Added)
         boinc_api.c
+
+Rom    Feb 3 2004
+    - Fixed warning while compiling with gcc.
+
+    api/
+        boincdiag.cpp,h