diff --git a/src/hash.cpp b/src/hash.cpp
index 4216157..4c83454 100644
--- a/src/hash.cpp
+++ b/src/hash.cpp
@@ -279,7 +279,7 @@ void file_data_hasher_t::hash()
 		MAP_FILE|
 #endif
 		MAP_SHARED,fd,0);
-	    if(fdht->base>0){		
+	    if(fdht->base>(void *)0){		
 		/* mmap is successful, so set the bounds.
 		 * if it is not successful, we default to reading the fd
 		 */
