# Add normalize\_path into the cmake -E

**URL:** https://discourse.cmake.org/t/add-normalize-path-into-the-cmake-e/7046
**Category:** Development
**Created:** [December 11, 2022, 10:40pm UTC](https://discourse.cmake.org/t/add-normalize-path-into-the-cmake-e/7046 "2022-12-11T22:40:27Z")
**Posts on this page:** 7
**Page:** 1

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### Author: ![leha-bot](https://discourse.cmake.org/user_avatar/discourse.cmake.org/leha-bot/32/921_2.png) [@leha-bot](https://discourse.cmake.org/u/leha-bot)
#### Post date: [December 11, 2022, 10:40pm UTC](https://discourse.cmake.org/t/add-normalize-path-into-the-cmake-e/7046/1 "2022-12-11T22:40:27Z")

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It would be very convenient, e.g., for some environments in which the mixed slashes could approach  
I got this at GitHub Actions with their `github.workflow` - it has backslashes on Windows, but it was mixed with forward slashes and CMake has reported an error:

```nohighlight
Run cmake -B build -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH="D:\a\std_version\std_version/build" -DCMAKE_MODULE_PATH="D:\a\std_version\std_version/build"
-- Building for: Visual Studio 17 2022
-- The CXX compiler identification is MSVC 19.34.31935.0
-- Detecting CXX compiler ABI info
CMake Error at D:/a/std_version/std_version/build/CMakeFiles/CMakeScratch/TryCompile-ej6is1/CMakeLists.txt:2 (set):
  Syntax error in cmake code at

    D:/a/std_version/std_version/build/CMakeFiles/CMakeScratch/TryCompile-ej6is1/CMakeLists.txt:2

  when parsing string

    D:\a\std_version\std_version/build

  Invalid character escape '\a'.

CMake Error at C:/Program Files/CMake/share/cmake-3.25/Modules/CMakeDetermineCompilerABI.cmake:57 (try_compile):
  Failed to configure test project build system.
Call Stack (most recent call first):
  C:/Program Files/CMake/share/cmake-3.25/Modules/CMakeTestCXXCompiler.cmake:26 (CMAKE_DETERMINE_COMPILER_ABI)
  CMakeLists.txt:4 (project)

-- Configuring incomplete, errors occurred!
See also "D:/a/std_version/std_version/build/CMakeFiles/CMakeOutput.log".

```

I’m thinking on making the simplest script with `cmake_path()` and executing it ad-hoc for normalizing paths, but the `cmake -E normalize_path <path>` would be more convenient. It looks like:

```cmake
cmake_minimum_required(VERSION 3.20)
# cmake -P NormalizePath.cmake <path> - <path> is argv3
cmake_path(SET FS_PATH NORMALIZE "${CMAKE_ARGV3}")
message("${FS_PATH}")

```

and can be launched via `cmake -P NormalizePath.cmake C:\some/wacky//weird/./path`.

p.s. Github Actions run on Windows with failure logs: [feat(CI): Test Github Actions on Windows and Macos (Take #2) · leha-bot/std\_version@b12824b · GitHub](https://github.com/leha-bot/std_version/actions/runs/3671099348/jobs/6206072882)

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### Author: ![ben.boeckel](https://discourse.cmake.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [December 12, 2022, 5:24pm UTC](https://discourse.cmake.org/t/add-normalize-path-into-the-cmake-e/7046/2 "2022-12-12T17:24:50Z")

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If you use `-DCMAKE_PREFIX_PATH:PATH` does it work (by telling CMake “this is a path” which then does `/`-normalization when inserting into the cache)? The problem here seems to be that the prefix path is written literally to the script where `\` is an escape character. CMake generally prefers to use `/` in paths and convert to `\` only where necessary.

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<div class="post-metadata">

### Author: ![leha-bot](https://discourse.cmake.org/user_avatar/discourse.cmake.org/leha-bot/32/921_2.png) [@leha-bot](https://discourse.cmake.org/u/leha-bot)
#### Post date: [December 12, 2022, 5:27pm UTC](https://discourse.cmake.org/t/add-normalize-path-into-the-cmake-e/7046/3 "2022-12-12T17:27:23Z")

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agreed, yes, and I think that instead of writing the script it’s better to call the proposed `cmake -E normalize_path ${{github.workspace}}/build`

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### Author: ![ben.boeckel](https://discourse.cmake.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [December 12, 2022, 5:41pm UTC](https://discourse.cmake.org/t/add-normalize-path-into-the-cmake-e/7046/4 "2022-12-12T17:41:36Z")

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The other thing CMake should do is escape variable values it writes for `try_compile` and friends.

Is there not a PowerShell command for doing this in the meantime?

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### Author: ![craig.scott](https://discourse.cmake.org/user_avatar/discourse.cmake.org/craig.scott/32/20_2.png) [@craig.scott](https://discourse.cmake.org/u/craig.scott)
#### Post date: [December 12, 2022, 8:53pm UTC](https://discourse.cmake.org/t/add-normalize-path-into-the-cmake-e/7046/5 "2022-12-12T20:53:23Z")

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> [@ben.boeckel](#):
>
> If you use `-DCMAKE_PREFIX_PATH:PATH` does it work (by telling CMake “this is a path” which then does `/`-normalization when inserting into the cache)?

That’s a bit of a lie, because formally `CMAKE_PREFIX_PATH` is a list of paths. That means `STRING` is the more correct variable type, since we have no other variable type for lists of anything. Quite often, a user might only put one path in `CMAKE_PREFIX_PATH`, which may make a `PATH` variable type appear to work. Maybe it’s fine when it only contains one value, but we shouldn’t really encourage this.

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<div class="post-metadata">

### Author: ![ben.boeckel](https://discourse.cmake.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [December 12, 2022, 9:26pm UTC](https://discourse.cmake.org/t/add-normalize-path-into-the-cmake-e/7046/6 "2022-12-12T21:26:30Z")

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Ideally, we’d have `PATHLIST` or something, but CMake and types…

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<div class="post-metadata">

### Author: ![leha-bot](https://discourse.cmake.org/user_avatar/discourse.cmake.org/leha-bot/32/921_2.png) [@leha-bot](https://discourse.cmake.org/u/leha-bot)
#### Post date: [December 13, 2022, 9:05am UTC](https://discourse.cmake.org/t/add-normalize-path-into-the-cmake-e/7046/7 "2022-12-13T09:05:32Z")

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I send a (maybe ad-hoc) fix for MODULE\_PATH: [https://gitlab.kitware.com/cmake/cmake/-/merge\_requests/8012](https://gitlab.kitware.com/cmake/cmake/-/merge_requests/8012)