diff --git a/src/libutil/nix_api_util.cc b/src/libutil/nix_api_util.cc
index 4f892637c..a5b575a3c 100644
--- a/src/libutil/nix_api_util.cc
+++ b/src/libutil/nix_api_util.cc
@@ -127,10 +127,7 @@ nix_err nix_err_info_msg(nix_c_context *context,
                                n);
 }
 
-nix_err nix_err_code(nix_c_context *context,
-                     const nix_c_context *read_context) {
-  if (context)
-    context->last_err_code = NIX_OK;
+nix_err nix_err_code(const nix_c_context *read_context) {
   return read_context->last_err_code;
 }
 
diff --git a/src/libutil/nix_api_util.h b/src/libutil/nix_api_util.h
index f626f2ccb..63854e4d8 100644
--- a/src/libutil/nix_api_util.h
+++ b/src/libutil/nix_api_util.h
@@ -253,12 +253,12 @@ nix_err nix_err_name(nix_c_context *context, const nix_c_context *read_context,
  *
  * Equivalent to reading the first field of the context.
  *
- * @param[out] context optional, the context to store errors in if this function
- * fails
+ * Does not fail
+ *
  * @param[in] read_context the context to retrieve the error message from
  * @return most recent error code stored in the context.
  */
-nix_err nix_err_code(nix_c_context *context, const nix_c_context *read_context);
+nix_err nix_err_code(const nix_c_context *read_context);
 
 /**
  *  @}