diff --git a/linker/debugger.cpp b/linker/debugger.cpp
index decc22c..c889544 100644
--- a/linker/debugger.cpp
+++ b/linker/debugger.cpp
@@ -151,7 +151,7 @@
   }
 
   char thread_name[MAX_TASK_NAME_LEN + 1]; // one more for termination
-  if (prctl(PR_GET_NAME, (unsigned long)thread_name, 0, 0, 0) != 0) {
+  if (prctl(PR_GET_NAME, reinterpret_cast<unsigned long>(thread_name), 0, 0, 0) != 0) {
     strcpy(thread_name, "<name unknown>");
   } else {
     // short names are null terminated by prctl, but the man page