# \[Suggestion\] Alert single-config generator users when they use --config

**URL:** https://discourse.cmake.org/t/suggestion-alert-single-config-generator-users-when-they-use-config/3036
**Category:** Development
**Created:** [March 28, 2021, 8:40pm UTC](https://discourse.cmake.org/t/suggestion-alert-single-config-generator-users-when-they-use-config/3036 "2021-03-28T20:40:51Z")
**Posts on this page:** 2
**Page:** 1

<div class="post-metadata">

### Author: ![anon45792294](https://discourse.cmake.org/letter_avatar_proxy/v4/letter/a/a587f6/32.png) [@anon45792294](https://discourse.cmake.org/u/anon45792294)
#### Post date: [March 28, 2021, 8:40pm UTC](https://discourse.cmake.org/t/suggestion-alert-single-config-generator-users-when-they-use-config/3036/1 "2021-03-28T20:40:51Z")

</div>

This post highlights a confusion for new cmake users.

> <https://stackoverflow.com/questions/66841390/cmake-build-types-make-no-difference>

They are using --config on a single configuration generator build. Which of course does nothing. Since --config is for multi-configuration generators.

How can we avoid this confusion for new users?

---

<div class="post-metadata">

### Author: ![brad.king](https://discourse.cmake.org/user_avatar/discourse.cmake.org/brad.king/32/11_2.png) [@brad.king](https://discourse.cmake.org/u/brad.king)
#### Post date: [March 29, 2021, 2:10pm UTC](https://discourse.cmake.org/t/suggestion-alert-single-config-generator-users-when-they-use-config/3036/2 "2021-03-29T14:10:56Z")

</div>

I think it would be reasonable to warn from `cmake --build . --config $config` on a single-configuration generator if `$config` does not match its `CMAKE_BUILD_TYPE`.

See [CONTRIBUTING.rst](https://gitlab.kitware.com/cmake/cmake/-/blob/master/CONTRIBUTING.rst) for contribution guidelines.