diff --git a/mozilla/mailnews/base/search/src/nsMsgSearchNews.cpp b/mozilla/mailnews/base/search/src/nsMsgSearchNews.cpp
index d01c9517c07..bb6784c86c0 100644
--- a/mozilla/mailnews/base/search/src/nsMsgSearchNews.cpp
+++ b/mozilla/mailnews/base/search/src/nsMsgSearchNews.cpp
@@ -522,7 +522,7 @@ void nsMsgSearchNews::ReportHit (nsIMsgDBHdr *pHeaders, const char *location)
 
 
 
-int nsMsgSearchNews::CompareArticleNumbers (const void *v1, const void *v2, void *data)
+int PR_CALLBACK nsMsgSearchNews::CompareArticleNumbers (const void *v1, const void *v2, void *data)
 {
 	// QuickSort callback to compare article numbers
 
diff --git a/mozilla/mailnews/base/search/src/nsMsgSearchNews.h b/mozilla/mailnews/base/search/src/nsMsgSearchNews.h
index 3e73965250a..cce9766f2b6 100644
--- a/mozilla/mailnews/base/search/src/nsMsgSearchNews.h
+++ b/mozilla/mailnews/base/search/src/nsMsgSearchNews.h
@@ -44,7 +44,7 @@ public:
 	
     PRBool DuplicateHit(PRUint32 artNum) ;
     void CollateHits ();
-    static int CompareArticleNumbers (const void *v1, const void *v2, void *data);
+    static int PR_CALLBACK CompareArticleNumbers (const void *v1, const void *v2, void *data);
     void ReportHit (nsIMsgDBHdr *pHeaders, const char *location);
 
 protected: