diff --git a/std_blocks/trig/ptrig.c b/std_blocks/trig/ptrig.c
index 34b76412..a2517747 100644
--- a/std_blocks/trig/ptrig.c
+++ b/std_blocks/trig/ptrig.c
@@ -235,9 +235,9 @@ int ptrig_handle_config(ubx_block_t *b)
 	assert(len >= 0);
 
 	if (len > 0) {
-		if (*stacksize < PTHREAD_STACK_MIN) {
-			ubx_err(b, "stacksize (%zd) less than PTHREAD_STACK_MIN (%d)",
-				*stacksize, PTHREAD_STACK_MIN);
+		if (*stacksize < (size_t) PTHREAD_STACK_MIN) {
+			ubx_err(b, "stacksize (%zd) less than PTHREAD_STACK_MIN (%zd)",
+				*stacksize, (size_t) PTHREAD_STACK_MIN);
 			goto out;
 		}