diff --git a/clang/include/clang-c/FatalErrorHandler.h b/clang/include/clang-c/FatalErrorHandler.h
--- a/clang/include/clang-c/FatalErrorHandler.h
+++ b/clang/include/clang-c/FatalErrorHandler.h
@@ -18,14 +18,14 @@
  * Installs error handler that prints error message to stderr and calls abort().
  * Replaces currently installed error handler (if any).
  */
-void clang_install_aborting_llvm_fatal_error_handler();
+void clang_install_aborting_llvm_fatal_error_handler(void);
 
 /**
  * Removes currently installed error handler (if any).
  * If no error handler is intalled, the default strategy is to print error
  * message to stderr and call exit(1).
  */
-void clang_uninstall_llvm_fatal_error_handler();
+void clang_uninstall_llvm_fatal_error_handler(void);
 
 #ifdef __cplusplus
 }