Conan: cmake_find_package generates invalid *_FOUND varable names

[Ri0n]

I have just one example. It's OpenSSL

Generated OpenSSL find module has

SET(OpenSSL_FOUND 1)

After this, code like

if(OPENSSL_FOUND)

doesn't work.

If I change it to

if(OpenSSL_FOUND)

it starts working.

So the comparisons are case sensitive and the fully uppercase variant is correct. Official OpenSSL find module also has if(OPENSSL_FOUND)

[Ri0n]

I've added replace_in_file("FindOpenSSL.cmake", "OpenSSL_", "OPENSSL_") as a workaround

[Ri0n]

Oh that was far from enough.. No idea what to do with openssl

[lasote]

Hi @Ri0n !

I think I need more information about what are you trying to do. Are you using the cmake_find_package generator, right? I think the issue is you are trying to use it like the "official" OpenSSL find package script. The cmake_find_package do not pretend to replace any official module, so the variables won't be the same and the usage has to be changed.

[Ri0n]

oh I see. That's the case. Is it possibe the packages will start providing custom templates for find module generation to be compatible with official?

[lasote]

If you want to use the official you can rely on the cmake_paths generator. It will indicate CMake where to find your libraries using the official one.

[SSE4]

CMake's find_package always drives me crazy. it's case-sensitive, and actually package name is case sensitive, as well as variable names are case-sensitive too. so, module is called FindOpenSSL.cmake, while variable are named like OPENSSL_FOUND.
meanwhile, if we take a look at an another package, e.g. boost, then package name is FindBoost.cmake, while variables are named like Boost_FOUND.
there is no logic, and it makes impossible to implement automation of generation of FindXXX.cmake modules properly (each module will require its own quirks, unfortunately).
question to vcpkg users - how does it work for vcpkg? how do they solve this problem?

[eliasdaler]

Agreed. It's now too simple to be really useful. I think that generator should support the following fields to be changed manually by user before generating FindX.cmake:

• library name - e.g. OpenSSL. Right now we have custom "openssl" Conan package which generates Findopenssl.cmake instead of FindOpenSSL.cmake.

• library name in variables - in the OpenSSL case we need to set it to "OPENSSL", in Boost case it'll be "Boost", etc. Generator should then set "OPENSSL_FOUND" and "Boost_FOUND" and the other variables. The default should be the library name in uppercase which seems to me most default Find* modules prefer.

[lasote]

It requires a parameter mechanism for the generators, but I agree for this generator is very very useful.

[eliasdaler]

Does it require big API changes? If this is a feature tha will be added on top of existing API, then maybe I may help implement this somehow? :)

[lasote]

It will require some deep analysis, I wouldn't recommend you to implement this one, but many thanks.