zlib.h file not found

[fboemer]

I'm trying to compile SEAL v3.6.1 with the below option:

cmake .. -DCMAKE_CXX_COMPILER=clang++-10 -DCMAKE_C_COMPILER=clang-10 -DCMAKE_INSTALL_PREFIX=../ -DBUILD_SHARED_LIBS=ON -DSEAL_BUILD_TESTS=ON

with cmake version 3.16.3 on Ubuntu 20.04 without zlib already installed.

make VERBOSE=1 yields the below error message:

[ 39%] Building CXX object CMakeFiles/seal_shared.dir/native/src/seal/util/ztools.cpp.o
/usr/bin/clang++-10  -Dseal_shared_EXPORTS -I/home/fboemer/repos/SEAL/native/src -I/home/fboemer/repos/SEAL/build/native/src -I/home/fboemer/repos/SEAL/thirdparty/msgsl-src/include -I/home/fboemer/repos/SEAL/thirdparty/zstd-src/lib -I/home/fboemer/repos/SEAL/thirdparty/zstd-src/lib/common  -O3 -DNDEBUG -fPIC   -pthread -std=gnu++17 -o CMakeFiles/seal_shared.dir/native/src/seal/util/ztools.cpp.o -c /home/fboemer/repos/SEAL/native/src/seal/util/ztools.cpp
/home/fboemer/repos/SEAL/native/src/seal/util/ztools.cpp:63:10: fatal error: 'zlib.h' file not found
#include "zlib.h"
         ^~~~~~~~

Notably, the include paths don't include /home/fboemer/repos/SEAL/thirdparty/zlib-src, which has zlib.h.

During the cmake command, I see

-- ZLIB: download ...
-- Looking for sys/types.h
-- Looking for sys/types.h - found
-- Looking for stdint.h
-- Looking for stdint.h - found
-- Looking for stddef.h
-- Looking for stddef.h - found
-- Check size of off64_t
-- Check size of off64_t - done
-- Looking for fseeko
-- Looking for fseeko - found
-- Looking for unistd.h
-- Looking for unistd.h - found
-- Renaming
--     /home/fboemer/repos/SEAL/thirdparty/zlib-src/zconf.h
-- to 'zconf.h.included' because this file is included with zlib
-- but CMake generates it automatically in the build directory.
-- Zstandard: download ...
-- ZSTD VERSION: 1.4.5

Installing zlib via sudo apt-get install libz-dev fixes the issue.

If I understand correctly, on systems without zlib installed SEAL should automatically download zlib and find zlib.h. If I'm mistaken, and zlib is required on the system, feel free to close the issue.

[WeiDaiWD]

Thanks, Fabian, this is a bug and right on time. It is fixed in the next release. Meanwhile, adding the following commands right after this line will fix this for you.

target_include_directories(seal_shared PRIVATE $<BUILD_INTERFACE:${zlib_SOURCE_DIR}>)
target_include_directories(seal_shared PRIVATE $<BUILD_INTERFACE:$<TARGET_PROPERTY:${zlib},BINARY_DIR>>)

[fboemer]

Thanks!