diff --git a/CoreSymbolication.h b/CoreSymbolication.h
index a413860..263e0bc 100644
--- a/CoreSymbolication.h
+++ b/CoreSymbolication.h
@@ -390,7 +390,7 @@ CSSymbolOwnerSetLoadTimestamp
 CSSymbolOwnerSetPath
 CSSymbolOwnerSetRelocationCount
  */
-CSSymbolOwnerSetTransientUserData(CSSymbolOwnerRef owner, uint32_t gen);
+int CSSymbolOwnerSetTransientUserData(CSSymbolOwnerRef owner, uint32_t gen);
  /*
 CSSymbolOwnerSetUnloadTimestamp
 */