diff --git a/src/rt/rust_log.cpp b/src/rt/rust_log.cpp
index 6fb1853e3bc..01e92e1f23d 100644
--- a/src/rt/rust_log.cpp
+++ b/src/rt/rust_log.cpp
@@ -269,8 +269,9 @@ void update_log_settings(void* crate_map, char* settings) {
                      n_dirs, &n_matches);
 
     if (n_matches < n_dirs) {
-        printf("warning: got %u RUST_LOG specs, enabled %u flags.",
-               n_dirs, n_matches);
+        printf("warning: got %" PRIdPTR " RUST_LOG specs, "
+               "enabled %" PRIdPTR " flags.",
+               (uintptr_t)n_dirs, (uintptr_t)n_matches);
     }
 
     free(buffer);