# rule about package variable naming
**URL:** https://discourse.cmake.org/t/rule-about-package-variable-naming/4087
**Category:** Usage
**Created:** [September 14, 2021, 1:07pm UTC](https://discourse.cmake.org/t/rule-about-package-variable-naming/4087 "2021-09-14T13:07:11Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@adaldev](https://discourse.cmake.org/u/adaldev)
#### Post date: [September 14, 2021, 1:07pm UTC](https://discourse.cmake.org/t/rule-about-package-variable-naming/4087/1 "2021-09-14T13:07:11Z")
Hi, is there a rule with respect to case for naming variables
\_INCLUDE\_DIRS and \_LIBRARIES
I have a non consistent behavior with Eigen3 where:
package name is Eigen3
and variables set after find\_package are
Eigen3\_VERSION\_MAJOR
EIGEN3\_VERSION\_MAJOR
EIGEN3\_INCLUDE\_DIRS
EIGEN3\_LIBRARIES
Is the uppercase the rule, is it package dependant?
thanks
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### Author:  [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [September 14, 2021, 1:47pm UTC](https://discourse.cmake.org/t/rule-about-package-variable-naming/4087/2 "2021-09-14T13:47:17Z")
That is…unfortunate. It is usually either the package name or all-uppercase. Having both is…weird.
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### Author:  [@marc.chevrier](https://discourse.cmake.org/u/marc.chevrier)
#### Post date: [September 14, 2021, 3:18pm UTC](https://discourse.cmake.org/t/rule-about-package-variable-naming/4087/3 "2021-09-14T15:18:52Z")
More precisely, the [documentation](https://cmake.org/cmake/help/latest/manual/cmake-developer.7.html#standard-variable-names) specifies that the prefix of the variables must be **exactly** the same as the package name.
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### Author:  [@adaldev](https://discourse.cmake.org/u/adaldev)
#### Post date: [September 20, 2021, 11:48am UTC](https://discourse.cmake.org/t/rule-about-package-variable-naming/4087/4 "2021-09-20T11:48:02Z")
Thanks to both of you.
I’ll stick to the documentation for my own packages.
Regards,
A.