diff --git a/checkin_notes b/checkin_notes
index fa517c89ca..b9dbdd985c 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -3263,3 +3263,11 @@ David  April 15 2008
     
     client/
         hostinfo_unix.C
+
+Charlie April 15 2008
+    - Fix is_file() to use S_ISREG() macro instead of incorrect 
+        (sbuf.st_mode & S_IFREG); fix is_dir() to use S_ISDIR() macro instead of 
+        incorrect (sbuf.st_mode & S_IFDIR).
+
+    lib/
+        filesys.C
diff --git a/lib/filesys.C b/lib/filesys.C
index af55b2f5fc..2893c27083 100644
--- a/lib/filesys.C
+++ b/lib/filesys.C
@@ -79,13 +79,13 @@ char boinc_failed_file[256];
 int is_file(const char* path) {
     struct stat sbuf;
     int retval = stat(path, &sbuf);
-    return (!retval && (sbuf.st_mode & S_IFREG));
+    return (!retval && S_ISREG(sbuf.st_mode));
 }
 
 int is_dir(const char* path) {
     struct stat sbuf;
     int retval = stat(path, &sbuf);
-    return (!retval && (sbuf.st_mode & S_IFDIR));
+    return (!retval && S_ISDIR(sbuf.st_mode));
 }
 
 #ifndef _WIN32