ZLIB_LIBRARY ZLIB_INCLUDE_DIR being ignored (LNK2019 errors) in OpenEXR\IlmImf\IlmImf.vcxproj

[mprevot]

In windows 10 x64; using VS2017; using cmake 3.13.14 and a powershell script.

I have multiple LNK2019 error, despite a correct configuration:

ImfDwaCompressor.obj : error LNK2019: unresolved external symbol compress2 referenced in function "private: int __cdecl
 Imf_2_3::DwaCompressor::compress(char const *,int,class Imath_2_3::Box<class Imath_2_3::Vec2<int> >,char const * &)" (
?compress@DwaCompressor@Imf_2_3@@AEAAHPEBDHV?$Box@V?$Vec2@H@Imath_2_3@@@Imath_2_3@@AEAPEBD@Z) [I:\lib\master-openexr\bu
ild\OpenEXR\IlmImf\IlmImf.vcxproj]
ImfDwaCompressor.obj : error LNK2019: unresolved external symbol compressBound referenced in function "private: int __c
decl Imf_2_3::DwaCompressor::compress(char const *,int,class Imath_2_3::Box<class Imath_2_3::Vec2<int> >,char const * &
)" (?compress@DwaCompressor@Imf_2_3@@AEAAHPEBDHV?$Box@V?$Vec2@H@Imath_2_3@@@Imath_2_3@@AEAPEBD@Z) [I:\lib\master-openex
r\build\OpenEXR\IlmImf\IlmImf.vcxproj]
ImfDwaCompressor.obj : error LNK2019: unresolved external symbol uncompress referenced in function "private: int __cdec
l Imf_2_3::DwaCompressor::uncompress(char const *,int,class Imath_2_3::Box<class Imath_2_3::Vec2<int> >,char const * &)
" (?uncompress@DwaCompressor@Imf_2_3@@AEAAHPEBDHV?$Box@V?$Vec2@H@Imath_2_3@@@Imath_2_3@@AEAPEBD@Z) [I:\lib\master-opene
xr\build\OpenEXR\IlmImf\IlmImf.vcxproj]
ImfPxr24Compressor.obj : error LNK2001: unresolved external symbol uncompress [I:\lib\master-openexr\build\OpenEXR\IlmI
mf\IlmImf.vcxproj]
ImfZip.obj : error LNK2001: unresolved external symbol uncompress [I:\lib\master-openexr\build\OpenEXR\IlmImf\IlmImf.vc
xproj]
ImfPxr24Compressor.obj : error LNK2019: unresolved external symbol compress referenced in function "private: int __cdec
l Imf_2_3::Pxr24Compressor::compress(char const *,int,class Imath_2_3::Box<class Imath_2_3::Vec2<int> >,char const * &)
" (?compress@Pxr24Compressor@Imf_2_3@@AEAAHPEBDHV?$Box@V?$Vec2@H@Imath_2_3@@@Imath_2_3@@AEAPEBD@Z) [I:\lib\master-opene
xr\build\OpenEXR\IlmImf\IlmImf.vcxproj]
ImfZip.obj : error LNK2001: unresolved external symbol compress [I:\lib\master-openexr\build\OpenEXR\IlmImf\IlmImf.vcxp
roj]
I:\lib\master-openexr\build\OpenEXR\IlmImf\Release\IlmImf-2_3.dll : fatal error LNK1120: 4 unresolved externals [I:\lib
\master-openexr\build\OpenEXR\IlmImf\IlmImf.vcxproj]

---

Repro:
using zlib 1.2.11, compiled in Win64 at I:\lib\zlib

I configure and build openexr with this script:

$target = "Visual Studio 15 2017 Win64"
$zlib_prefix = "I:\lib\zlib"

function configure {
	cmake.exe -G $target -T v141, host=x64 -j8 `
		-DZLIB_LIBRARY="${zlib_prefix}\lib" -DZLIB_INCLUDE_DIR="${zlib_prefix}\include" `
		-DOPENEXR_BUILD_PYTHON_LIBS=0 -DCMAKE_INSTALL_PREFIX="I:\lib\openexr" `
		..
}

function build {
	"build openexr debug"
	MSBuild.exe OpenEXR.sln /verbosity:m /m
	"build openexr release"
	MSBuild.exe OpenEXR.sln /p:Configuration=Release /verbosity:m /m
}

function install {
	"install openexr debug"
	MSBuild.exe INSTALL.vcxproj /verbosity:m /m
	"install openexr release"
	MSBuild.exe INSTALL.vcxproj /p:Configuration=Release /verbosity:m /m
}

if (!(test-path build)) {
	New-Item -ItemType Directory build
}
Set-Location build
configure
build
#install
Set-Location ..

Proof: hand-edit IlmImf.vcxproj to use the zlib.lib and zlibd.lib provided works.

[meshula]

apparent the cmake zlib find script looks for a ZLIB_ROOT variable?

/~https://github.com/Kitware/CMake/blob/master/Modules/FindZLIB.cmake

[mprevot]

@meshula Indeed, first, but ZLIB_LIBRARY ZLIB_INCLUDE_DIR are evaluated after (it seems they are not in the end) and they used by other projects correctly and are documented.

[meshula]

That's true. The link errors don't explain why the symbols are missing. Could you attach your CMakeCache.txt file? It might provide some clues about what's going on.

[mprevot]

CMakeCache.txt

[mprevot]

@meshula last line of the OP:

Proof: hand-edit IlmImf.vcxproj to use the zlib.lib and zlibd.lib provided works.

[mprevot]

@meshula Adding -DZLIB_ROOT="I:\lib\zlib" in the configure command (cmake.exe -G $target -T v141, host=x64 -j16 ...) does not solve the problem any better.

[meshula]

Thanks for posting the file. I don't have any more information for you yet. One more question, are you building from github top of tree, or from source obtained some other way?

[mprevot]

Yes. I downloaded the sources from master the 14th of april.

[meshula]

I wanted to double check if OpenEXR can be built at all with zlib when both are fetched fresh. I did the following:

cd c:\Projects\Lucasfilm
git clone /~https://github.com/madler/zlib.git
cd c:\Projects\Lucasfilm\build\zlib
cmake -G "Visual Studio 15 2017 Win64" c:\Projects\Lucasfilm\zlib -DCMAKE_INSTALL_PREFIX=c:\Projects\Lucasfilm\install
cmake --build . --config Release --target install
cd c:\Projects\Lucasfilm
git clone /~https://github.com/openexr/openexr.git
cd build\openexr
cmake -G "Visual Studio 15 2017 Win64" -DOPENEXR_BUILD_PYTHON_LIBS=OFF -DOPENEXR_ENABLE_TESTS=OFF -DCMAKE_INSTALL_PREFIX=c:\Projects\Lucasfilm\install ..\..\openexr
cmake --build . --config Release --target install

and I got a successful build. The primary difference is that I asked cmake to install zlib into the directory I will build openexr into, and relied on the CMAKE_INSTALL_PREFIX variable to help cmake find the zlib installation. I am wondering if you could attempt the same, to try to isolate first of all whether you are able to build at all?

[mprevot]

As I mentionned in the OP, I added in the IlmImf project the path I:\lib\zlib\lib to search lib files (*.lib) and zlib.lib and zlibd.lib (for debug build) references by hand and this allows a successful build.

This is what I meant by:

Proof: hand-edit IlmImf.vcxproj to use the zlib.lib and zlibd.lib provided works.

The problem is that ZLIB_LIBRARY ZLIB_INCLUDE_DIR are being ignored since they should be added in the IlmImf project to allow the successful build. IMO CMakeLists.txt needs few corrections.

[meshula]

Yes, I did see your original comment, and reminders on that point. The cmake scripts have undergone significant revision recently and regressions are possible. My point is to establish if a conventional build works, or if it is necessary to patch a conventional build as well. I'm now satisfied that the conventional build does work as expected, and so agree with you that revisions are possible to support your configuration.

[meshula]

Okay, I went through all the documentation I could find, and the implementation, and compared a bunch of projects on github, some of which do indeed use ZLIB_LIBRARY as an input.

quick summary

1. ZLIB_LIBRARIES is the variable to set, according to the documentation, and it's what OpenEXR expects. I think this is the right thing to do, even if some projects don't do it.
2. OpenEXR erroneously uses ZLIB_INCLUDE_DIR, which is an error in the OpenEXR Cmake files and should be corrected.

details:

https://cmake.org/cmake/help/latest/module/FindZLIB.html

OpenExr looks for ZLIB_INCLUDE_DIR in OpenEXR/CMakeLists.txt, but according to the FindZLIB documentation, it should be looking for ZLIB_INCLUDE_DIRS.

 MACRO(SET_ILMBASE_INCLUDE_DIRS _target)
    TARGET_INCLUDE_DIRECTORIES(${_target}
     PRIVATE ${ZLIB_INCLUDE_DIR}
     PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/../config
     PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/../../IlmBase/config

So this is an error in OpenEXR's cmake scripts.

According to the documentation, using ZLIB_ROOT should be sufficient to set ZLIB_INCLUDE_DIRS and ZLIB_LIBRARIES. Nonetheless, since you only had to edit the vcxproj to add zlib references, setting -DZLIB_LIBRARIES in your script instead of ZLIB_LIBRARY should solve your problem.

I understand that other projects are successfully using ZLIB_LIBRARY, but the implementation itself

/~https://github.com/Kitware/CMake/blob/master/Modules/FindZLIB.cmake

specifies ZLIB_LIBRARY as an input to FindZLIB, used to set ZLIB_LIBRARIES.

Result Variables
^^^^^^^^^^^^^^^^

This module defines the following variables:

::

  ZLIB_INCLUDE_DIRS   - where to find zlib.h, etc.
  ZLIB_LIBRARIES      - List of libraries when using zlib.
  ZLIB_FOUND - True if zlib found.

As an interesting point in comparison, conan's FindZlib script was updated to use ZLIB_LIBRARIES only, which broke some of their dependent packages, so they had to add ZLIB_LIBRARY back in as an exposed variable. /~https://github.com/conan-community/community/issues/153 They too preferred to stick to documented outputs.

[mprevot]

Configuring with cmake and ZLIB_LIBRARIES set correctly works flawlessly. Other ZLIB_* unnecessar variables can be stripped out. M Le ven. 19 avr. 2019 à 08:23, Nick Porcino <notifications@github.com> a écrit :

…

tl/dr 1. ZLIB_LIBRARIES is the variable to set, according to the documentation, and it's what OpenEXR expects. 2. OpenEXR erroneously uses ZLIB_INCLUDE_DIR, which is an error in the OpenEXR Cmake files and should be corrected. details: https://cmake.org/cmake/help/latest/module/FindZLIB.html OpenExr looks for ZLIB_INCLUDE_DIR in OpenEXR/CMakeLists.txt, but according to the FindZLIB documentation, it should be looking for ZLIB_INCLUDE_DIRS. MACRO(SET_ILMBASE_INCLUDE_DIRS _target) TARGET_INCLUDE_DIRECTORIES(${_target} PRIVATE ${ZLIB_INCLUDE_DIR} PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/../config PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/../../IlmBase/config So this is an error in OpenEXR's cmake scripts. According to the documentation, using ZLIB_ROOT should be sufficient to set ZLIB_INCLUDE_DIRS and ZLIB_LIBRARIES. Nonetheless, since you only had to edit the vcxproj to add zlib references, setting -DZLIB_LIBRARIES in your script instead of ZLIB_LIBRARY should solve your problem. I understand that other projects are successfully using ZLIB_LIBRARY, but the implementation itself /~https://github.com/Kitware/CMake/blob/master/Modules/FindZLIB.cmake specifies ZLIB_LIBRARY as an input to FindZLIB, used to set ZLIB_LIBRARIES. Result Variables ^^^^^^^^^^^^^^^^ This module defines the following variables: :: ZLIB_INCLUDE_DIRS - where to find zlib.h, etc. ZLIB_LIBRARIES - List of libraries when using zlib. ZLIB_FOUND - True if zlib found. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#379 (comment)>, or mute the thread </~https://github.com/notifications/unsubscribe-auth/AB74YOR74QUJJBTPNMR6NTTPRFQPPANCNFSM4HGB6SAA> .

[meshula]

Great :) Glad to hear you are unblocked!