[CMake] [cmake-developers] Debugging find_package() search behavior?

[Robert Dailey]

I think the discrepancy here might be config vs module find mode. The
documentation I linked seems to be for config mode only, however I'm
utilizing the CMake-shipped FindZLIB.cmake module to find this
particular library. Does this offer no guarantees on how
CMAKE_PREFIX_PATH is used?

On Tue, Aug 29, 2017 at 10:11 AM, Robert Dailey
<rcdailey.lists at gmail.com> wrote:
> What I'm hoping for is that find_package() follows the rules it
> documents here:
> https://cmake.org/cmake/help/v3.6/command/find_package.html
>
> Specifically, it states it searches these paths (and that <name> is
> treated case-insensitive):
>
> <prefix>/                                               (W)
> <prefix>/(cmake|CMake)/                                 (W)
> <prefix>/<name>*/                                       (W)
> <prefix>/<name>*/(cmake|CMake)/                         (W)
> <prefix>/(lib/<arch>|lib|share)/cmake/<name>*/          (U)
> <prefix>/(lib/<arch>|lib|share)/<name>*/                (U)
> <prefix>/(lib/<arch>|lib|share)/<name>*/(cmake|CMake)/  (U)
>
> If this is true, then the 3rd one from the top should be a match,
> because <prefix> is set to:
>
> E:/code/frontend/msvc_2015/third_party/installed
>
> And <name> is set to ZLIB in find_package() first argument, so it
> should be adding that to the end.
>
> I need to keep CMAKE_PREFIX_PATH pointing to the parent directory
> ("installed") because I have other libraries that get installed in
> that directory, each with their own directory to contain their
> installation files. If find_package() is appending <name> to <prefix>
> like it says it should, it should find each one of them without
> switching the value of CMAKE_PREFIX_PATH.
>
> Am I misunderstanding something?
>
>
> On Tue, Aug 29, 2017 at 10:06 AM, David Cole <DLRdave at aol.com> wrote:
>> Shouldn't the "/zlib" at the end be included in your CMAKE_PREFIX_PATH?
>>
>> On Tue, Aug 29, 2017 at 11:01 AM, Robert Dailey
>> <rcdailey.lists at gmail.com> wrote:
>>> On Tue, Aug 29, 2017 at 9:56 AM, Brad King <brad.king at kitware.com> wrote:
>>>> On 08/29/2017 10:55 AM, Brad King wrote:
>>>>> On 08/29/2017 10:48 AM, Robert Dailey wrote:
>>>>>> CMAKE_PREFIX_PATH: E:/code/frontend/msvc_2015/third_party/installed
>>>>>> CMAKE_FIND_ROOT_PATH: E:/code/frontend/msvc_2015/third_party/installed
>>>>>
>>>>> I'm not sure how CMAKE_FIND_ROOT_PATH's path re-rooting interacts with
>>>>> drive letters on Windows.
>>>>
>>>> Oops, sent too soon.
>>>>
>>>> CMAKE_FIND_ROOT_PATH should not be necessary here.  It's for cross-compiling
>>>> to re-root paths like `/usr` into some prefix on the host.
>>>>
>>>> -Brad
>>>
>>> Ok but even if I remove that, find_package() still isn't working......
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