diff --git a/artsc/artsdsp.c b/artsc/artsdsp.c
index 4713d84..79ff1f8 100644
--- a/artsc/artsdsp.c
+++ b/artsc/artsdsp.c
@@ -484,7 +484,7 @@ int ioctl (int fd, ioctl_request_t request, ...)
 #endif
 
         default:
-          artsdspdebug("aRts: unhandled /dev/dsp ioctl (%lx - %p)\n",request, argp);
+          artsdspdebug("aRts: unhandled /dev/dsp ioctl (%lx - %p)\n", (unsigned long)request, argp);
           break;
         }