diff --git a/libcoz/real.cpp b/libcoz/real.cpp
index 8e7c063..057acd9 100644
--- a/libcoz/real.cpp
+++ b/libcoz/real.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "real.h"
+#include "ccutil/log.h"
 
 #include <dlfcn.h>
 
@@ -37,6 +38,7 @@ static void* pthread_handle = NULL;   //< The `dlopen` handle to libpthread
 static void* get_pthread_handle() {
   if(pthread_handle == NULL && !__atomic_exchange_n(&in_dlopen, true, __ATOMIC_ACQ_REL)) {
     pthread_handle = dlopen("libpthread.so.0", RTLD_NOW | RTLD_GLOBAL);
+    REQUIRE(pthread_handle != NULL) << dlerror();
     __atomic_store_n(&in_dlopen, false, __ATOMIC_RELEASE);
   }