# find\_package(Python3) is not finding the correct python
**URL:** https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563
**Category:** Code
**Tags:** os:linux
**Created:** [April 4, 2024, 9:10am UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563 "2024-04-04T09:10:56Z")
**Posts on this page:** 11
**Page:** 1
### Author:  [@mdorier](https://discourse.cmake.org/u/mdorier)
#### Post date: [April 4, 2024, 9:10am UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/1 "2024-04-04T09:10:56Z")
I have the following minimal CMakeLists.txt:
```auto
cmake_minimum_required (VERSION 3.8)
project (myproject C CXX)
find_package (Python3 COMPONENTS Interpreter Development REQUIRED)
```
I use spack ([https://spack.io/](https://spack.io/)) to manage my dependencies, so I have a spack environment activated which contains a build of python 3.11.7, that is, this version of python is in my `$PATH`, `python --version` gives me “3.11.7”, `$PYTHONPATH` contains the correct path for this python build, and `$LD_LIBRARY_PATH` contains the path where libpython3.11.so can be found (and it does not contain “/usr/lib” or any other system path).
When I call cmake, however, I’m getting this error:
```auto
-- The C compiler identification is GNU 11.4.0
-- The CXX compiler identification is GNU 11.4.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at /usr/share/cmake-3.22/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
Could NOT find Python3 (missing: Python3_INCLUDE_DIRS Development
Development.Module Development.Embed) (found version "3.10.12")
Call Stack (most recent call first):
/usr/share/cmake-3.22/Modules/FindPackageHandleStandardArgs.cmake:594 (_FPHSA_FAILURE_MESSAGE)
/usr/share/cmake-3.22/Modules/FindPython/Support.cmake:3180 (find_package_handle_standard_args)
/usr/share/cmake-3.22/Modules/FindPython3.cmake:490 (include)
CMakeLists.txt:3 (find_package)
```
The `found version "3.10.12"` makes me think that cmake is finding the version of python that is in “/usr/bin”, even though “/usr/bin” comes much later in my `$PATH` than the path to the python version I’m trying to use. The system-provided python doesn’t have the development libraries, which is why cmake fails, I believe.
Could you help me figure out why FindPython3.cmake finds this system-provided Python instead of the one I want to use, and how to fix this problem?
---
### Author:  [@marc.chevrier](https://discourse.cmake.org/u/marc.chevrier)
#### Post date: [April 4, 2024, 9:57am UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/2 "2024-04-04T09:57:34Z")
What names are installed for `python` from `spack`? Is `python3` or `python3.11` available from `spack`?
Can you try to set the variable `Python3_FIND_STRATEGY` to value `LOCATION`? From your snippet, the behavior for the find strategy is `VERSION` so can get is the observed result if `spack` do not install versioned name (.i.e. `python3.11`).
---
### Author:  [@mdorier](https://discourse.cmake.org/u/mdorier)
#### Post date: [April 4, 2024, 12:02pm UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/3 "2024-04-04T12:02:24Z")
Setting `Python3_FIND_STRATEGY` to `LOCATION` works. Is that the solution to go for, moving forward? I still don’t understand why cmake picks 3.10 when the only variable that references it is `$PATH`, but “/usr/bin” is at the end of it…
Spack does install python, python3, and python3.11. Doing `which pythonX` for these pythons executables all yields the spack-installed ones.
Something I suspected to happen is that in `/usr/share/cmake-3.22/Modules/FindPython/Support.cmake`, near the beginning of the file, I see this:
```auto
set(_${_PYTHON_PREFIX}_VERSIONS 3.10 3.9 3.8 3.7 3.6 3.5 3.4 3.3 3.2 3.1 3.0)
```
I added 3.11 in the list, but it didn’t change anything.
---
### Author:  [@marc.chevrier](https://discourse.cmake.org/u/marc.chevrier)
#### Post date: [April 4, 2024, 12:25pm UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/4 "2024-04-04T12:25:27Z")
The fact that version `3.11` is not defined is the root of the problem.
Anyway, to get your expected behavior, I recommend you to set variable `Python3_FIND_STRATEGY` with value `LOCATION` or set policy `CMP0094` to `NEW`.
By the way, `Python3` version `3.11` was added in `CMake` version `3.22.2`.
To finish, I am surprised that adding `3.11` didn’t change anything. Did you clean-up the environment (i.e. at least removing `CMakeCache.txt` file) before you try?
---
### Author:  [@mdorier](https://discourse.cmake.org/u/mdorier)
#### Post date: [April 4, 2024, 12:28pm UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/5 "2024-04-04T12:28:34Z")
Yes, I cleaned up everything (I reconfirmed just now).
---
### Author:  [@bradbell](https://discourse.cmake.org/u/bradbell)
#### Post date: [August 14, 2024, 12:43pm UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/6 "2024-08-14T12:43:02Z")
I am having a similar problem on Fedora 39 with cmake 3.27.7. Here is the default verison of python:
```auto
python --version
Python 3.12.3
```
I am using
```auto
FIND_PACKAGE(Python COMPONENTS Interpreter Development)
```
and get the following output:
```auto
-- Found Python: /usr/bin/python3.13 (found version "3.13.0")
```
Looking in /usr/bin I see
```auto
ls -l /usr/bin | grep 'python3.1[0-9]$'
lrwxrwxrwx. 1 root root 10 Apr 16 17:00 python3 -> python3.12
-rwxr-xr-x. 1 root root 15880 Apr 16 17:00 python3.10
-rwxr-xr-x. 1 root root 15880 Apr 16 17:00 python3.11
-rwxr-xr-x. 1 root root 15880 Apr 16 17:00 python3.12
-rwxr-xr-x. 1 root root 15888 Apr 16 17:00 python3.13
```
1, It seems to me that FindPython should (by default) pick up the version correspoding to the python3 command.
2. I cannot find the documentation or an example for Python3\_FIND\_STRATEGY so I do know how to use it to get FindPython to get version 3.12 of python.
---
### Author:  [@marc.chevrier](https://discourse.cmake.org/u/marc.chevrier)
#### Post date: [August 14, 2024, 1:23pm UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/7 "2024-08-14T13:23:11Z")
To achieve what you want, set `Python_FIND_UNVERSIONED_NAMES` variable to `FIRST`.
---
### Author:  [@bradbell](https://discourse.cmake.org/u/bradbell)
#### Post date: [August 14, 2024, 2:22pm UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/8 "2024-08-14T14:22:16Z")
CMakeLists.txt:
```auto
cmake_minimum_required (VERSION 3.8)
project (myproject C CXX)
set( Python_FIND_UNVERSIONED_NAMES FIRST )
find_package (Python3 COMPONENTS Interpreter Development REQUIRED )
```
CMake output:
```auto
-- The C compiler identification is GNU 13.2.1
-- The CXX compiler identification is GNU 13.2.1
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found Python3: /usr/bin/python3.13 (found version "3.13.0") found components: Interpreter Development Development.Module Development.Embed
-- Configuring done (0.5s)
-- Generating done (0.0s)
-- Build files have been written to: /home/bradbell/trash/cmake
```
---
### Author:  [@marc.chevrier](https://discourse.cmake.org/u/marc.chevrier)
#### Post date: [August 14, 2024, 3:58pm UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/9 "2024-08-14T15:58:39Z")
You don’t get the expected result for t0i reasons:
1. You have changed the module used between the examples (`Python` and `Python3`). Variable’s prefix must be used accordingly with the module name.
2. Because you request version 3.8 for `CMake`.
In this case, `Python3_FIND_STRATEGY` variable is set to `VERSION` which means that, for each possible python version (starting from the most recent), all locations are searched for it so it is normal that version `3.13` is returned.
By setting `Python3_FIND_STRATEGY` variable to `LOCATION`, all possible versions, ordered from the most recent to the least one, will be searched in all locations. In this case, by setting `Python3_FIND_UNVERSIONED_NAMES` variable to `FIRST`, the unversioned python will be selected.
---
### Author:  [@bradbell](https://discourse.cmake.org/u/bradbell)
#### Post date: [August 14, 2024, 5:09pm UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/10 "2024-08-14T17:09:58Z")
Thanks. I thought that the minimum requires cmake version would only check that your version was recent enough. I did not realize that it actually changes how ones version of cmake behaves.
CMakeLists.txt
```auto
# Must use 3.15 or higher in order to find python3.12 instead of python3.13
cmake_minimum_required (VERSION 3.15)
project (myproject C CXX)
set( Python_FIND_UNVERSIONED_NAMES FIRST )
find_package (Python COMPONENTS Interpreter Development REQUIRED )
```
Results in
```auto
-- Found Python: /usr/bin/python3 (found version "3.12.3") found components: Interpreter Development Development.Module Development.Embed
```
---
### Author:  [@duaneellis\_inno](https://discourse.cmake.org/u/duaneellis_inno)
#### Post date: [August 19, 2024, 4:00pm UTC](https://discourse.cmake.org/t/find-package-python3-is-not-finding-the-correct-python/10563/11 "2024-08-19T16:00:56Z")
We solve this by other ways…
we require the user to have an ENV var that points to the PythonEXE to use.
ie: COMPANY\_PYTHON3\_EXE=/absolute/path/to/python.
This may be a shell script that “sanitizes” the ENV variables.
Why? Because some tools {MicroSemi} install a private copy of Python as part of their eclipse install and then they set various PYTHON VARS like PYTHON\_HOME to point to their directories.
And for example PY VIRT env does not work because - a) it really loads another sub-shell, and well - then you run python in that sub-shell… and (b) Some tools [xilinx] reset your PATH to have the standard path… and other things… Besides using something that creates a subshell - means you cannot use your desktop icons to launch tools and have it work.
So - instead - we use (a) env variable to the executable (b) that executable [script] must sanitize the ENV vars before launching python
In CMake - we read the ENV var and set the CMAKE variable for the python exe