diff --git a/crypto/ui/ui.c b/crypto/ui/ui.c
index a6cb2e30cc7..68a54aabaaf 100644
--- a/crypto/ui/ui.c
+++ b/crypto/ui/ui.c
@@ -19,17 +19,17 @@ void UI_free(UI *ui) {
 
 int UI_add_input_string(UI *ui, const char *prompt, int flags,
         char *result_buf, int minsize, int maxsize) {
-  return 0;
+  return -1;
 }
 int UI_add_verify_string(UI *ui, const char *prompt, int flags,
         char *result_buf, int minsize, int maxsize, const char *test_buf) {
-  return 0;
+  return -1;
 }
 
 int UI_add_info_string(UI *ui, const char *text) {
-  return 0;
+  return -1;
 }
 
 int UI_process(UI *ui) {
-  return 0;
+  return -1;
 }
diff --git a/include/openssl/ui.h b/include/openssl/ui.h
index 6542fa3c8af..a9a3e826d14 100644
--- a/include/openssl/ui.h
+++ b/include/openssl/ui.h
@@ -22,18 +22,18 @@ OPENSSL_EXPORT OPENSSL_DEPRECATED UI *UI_new(void);
 /// UI_free invokes OPENSSL_free on its parameter.
 OPENSSL_EXPORT OPENSSL_DEPRECATED void UI_free(UI *ui);
 
-/// UI_add_input_string does nothing, always returns 0.
+/// UI_add_input_string does nothing, always returns -1 for failure.
 OPENSSL_EXPORT OPENSSL_DEPRECATED int UI_add_input_string(UI *ui, const char *prompt, int flags,
         char *result_buf, int minsize, int maxsize);
 
-/// UI_add_verify_string does nothing, always returns 0.
+/// UI_add_verify_string does nothing, always returns -1 for failure.
 OPENSSL_EXPORT OPENSSL_DEPRECATED int UI_add_verify_string(UI *ui, const char *prompt, int flags,
         char *result_buf, int minsize, int maxsize, const char *test_buf);
 
-/// UI_add_info_string does nothing, always returns 0.
+/// UI_add_info_string does nothing, always returns -1 for failure.
 OPENSSL_EXPORT OPENSSL_DEPRECATED int UI_add_info_string(UI *ui, const char *text);
 
-/// UI_process does nothing, always returns 0.
+/// UI_process does nothing, always returns -1 for failure.
 OPENSSL_EXPORT OPENSSL_DEPRECATED int UI_process(UI *ui);
 
 #endif //UI_H