diff --git a/appl/dceutils/testpag.c b/appl/dceutils/testpag.c
index 4613fba5e..df7f2f4a3 100644
--- a/appl/dceutils/testpag.c
+++ b/appl/dceutils/testpag.c
@@ -141,7 +141,7 @@ main(argc, argv)
         "FILE:/opt/dcelocal/var/security/creds/dcecred_%8.8x", 
         pag);
       esetenv("KRB5CCNAME",ccname,1);
-      execl("/bin/csh","csh",0);
+      execl("/bin/csh", "csh", NULL);
     }
     else {
       fprintf(stderr," Not a good pag value\n");
diff --git a/appl/telnet/telnetd/sys_term.c b/appl/telnet/telnetd/sys_term.c
index 1d3f0bd06..f05eb7090 100644
--- a/appl/telnet/telnetd/sys_term.c
+++ b/appl/telnet/telnetd/sys_term.c
@@ -1884,7 +1884,7 @@ cleantmpdir(jid, tpath, user)
 	       tpath);
 	break;
     case 0:
-	execl(CLEANTMPCMD, CLEANTMPCMD, user, tpath, 0);
+	execl(CLEANTMPCMD, CLEANTMPCMD, user, tpath, NULL);
 	syslog(LOG_ERR, "TMPDIR cleanup(%s): execl(%s) failed: %m\n",
 	       tpath, CLEANTMPCMD);
 	exit(1);
diff --git a/appl/xnlock/xnlock.c b/appl/xnlock/xnlock.c
index e9c75fe12..3ba32abdd 100644
--- a/appl/xnlock/xnlock.c
+++ b/appl/xnlock/xnlock.c
@@ -297,8 +297,8 @@ zrefresh(void)
       return -1;
   case 0:
       /* Child */
-      execlp("zrefresh", "zrefresh", 0);
-      execl(BINDIR "/zrefresh", "zrefresh", 0);
+      execlp("zrefresh", "zrefresh", NULL);
+      execl(BINDIR "/zrefresh", "zrefresh", NULL);
       return -1;
   default:
       /* Parent */