diff --git a/libs/lpac-jni/src/main/jni/lpac-jni/lpac-jni.h b/libs/lpac-jni/src/main/jni/lpac-jni/lpac-jni.h
index 6895aef..1915c5e 100644
--- a/libs/lpac-jni/src/main/jni/lpac-jni/lpac-jni.h
+++ b/libs/lpac-jni/src/main/jni/lpac-jni/lpac-jni.h
@@ -4,6 +4,9 @@
 #include <pthread.h>
 #include <jni.h>
 
+_Static_assert(sizeof(void *) <= sizeof(jlong),
+               "jlong must be big enough to hold a platform raw pointer");
+
 struct lpac_jni_ctx {
     jobject apdu_interface;
     jobject http_interface;