Clarify that configuration_data()'s copy is immutable

1 files changed, 1 insertions, 0 deletions

diff --git a/docs/markdown/Configuration.md b/docs/markdown/Configuration.md
index d8fa54e..89f423c 100644
--- a/docs/markdown/Configuration.md
+++ b/docs/markdown/Configuration.md
@@ -39,6 +39,7 @@ use a single `configuration_data` object as many times as you like,
 but it becomes immutable after being passed to the `configure_file`
 function. That is, after it has been used once to generate output the
 `set` function becomes unusable and trying to call it causes an error.
+Copy of immutable `configuration_data` is still immutable.
 
 For more complex configuration file generation Meson provides a second
 form. To use it, put a line like this in your configuration file.