diff --git a/sched.c b/sched.c
index 45ef11c..fce9f06 100644
--- a/sched.c
+++ b/sched.c
@@ -534,7 +534,8 @@ dispatch_filehandlers(int nfd, fd_set *read_fds, fd_set *write_fds, fd_set *exce
     if (except_fds && FD_ISSET(fd, except_fds)) {
       /* This descriptor has an exception, dispatch its handler */
       ptr = (FileHandlerEntry *)ARR_GetElement(file_handlers, fd);
-      (ptr->handler)(fd, SCH_FILE_EXCEPTION, ptr->arg);
+      if (ptr->handler)
+        (ptr->handler)(fd, SCH_FILE_EXCEPTION, ptr->arg);
       nfd--;
 
       /* Don't try to read from it now */
@@ -547,14 +548,16 @@ dispatch_filehandlers(int nfd, fd_set *read_fds, fd_set *write_fds, fd_set *exce
     if (read_fds && FD_ISSET(fd, read_fds)) {
       /* This descriptor can be read from, dispatch its handler */
       ptr = (FileHandlerEntry *)ARR_GetElement(file_handlers, fd);
-      (ptr->handler)(fd, SCH_FILE_INPUT, ptr->arg);
+      if (ptr->handler)
+        (ptr->handler)(fd, SCH_FILE_INPUT, ptr->arg);
       nfd--;
     }
 
     if (write_fds && FD_ISSET(fd, write_fds)) {
       /* This descriptor can be written to, dispatch its handler */
       ptr = (FileHandlerEntry *)ARR_GetElement(file_handlers, fd);
-      (ptr->handler)(fd, SCH_FILE_OUTPUT, ptr->arg);
+      if (ptr->handler)
+        (ptr->handler)(fd, SCH_FILE_OUTPUT, ptr->arg);
       nfd--;
     }
   }