Compile Crypto++ library for OS X Xcode project

Question

I have downloaded Crypto++ and I am trying to build it so that I can use it in a C++ Xcode project.

I compiled using just "make" command and included libcryptopp.a in my c++ project of my xcode. But it is giving errors:

Undefined symbols for architecture i386:   "CryptoPP::HashFilter::HashFilter(CryptoPP::HashTransformation&,
 CryptoPP::BufferedTransformation*, bool, int, std::__1::basic_string<char, std::__1::char_traits<char>,
 std::__1::allocator<char> > const&, std::__1::basic_string<char, std::__1::char_traits<char>,
 std::__1::allocator<char> > const&)", referenced from:
 ...

Answer 1

I compiled using just "make" command and included libcryptopp.a in my c++ project of my xcode. But it is giving errors ...

As @halfelf said, you need to use LLVM's runtime (libc++) because that is what Xcode uses. Depending on the Crypto++ version you have, you may (or may not) be using GNU's runtime (libstdc++).

The easiest way to fix this is to checkout Master. Its OK to work from Master because its mostly stable and only suffers an occasional break (most development occurs on a separate branch).

$ git clone https://github.com/weidai11/cryptopp
Cloning into 'cryptopp'...
remote: Counting objects: 9116, done.
remote: Total 9116 (delta 0), reused 0 (delta 0), pack-reused 9116
Receiving objects: 100% (9116/9116), 8.05 MiB | 6.53 MiB/s, done.
Resolving deltas: 100% (6406/6406), done.
Checking connectivity... done.

Using Master is required because older versions of Crypto++ did not honor user's CXX and CXXFLAGS. You used to have to edit the makefile to fix it.

Then, perform the following:

export CXXFLAGS="-DNDEBUG -g2 -O2 -stdlib=libc++"
$ CXX=clang++ make -j 4
clang++ -DNDEBUG -g2 -O2 -stdlib=libc++ -fPIC -march=native -pipe -c cryptlib.cpp
clang++ -DNDEBUG -g2 -O2 -stdlib=libc++ -fPIC -march=native -pipe -c cpu.cpp
clang++ -DNDEBUG -g2 -O2 -stdlib=libc++ -fPIC -march=native -pipe -c shacal2.cpp
clang++ -DNDEBUG -g2 -O2 -stdlib=libc++ -fPIC -march=native -pipe -c md5.cpp
...

You have to set Debug/Release build, Symbol level and Optimization level. The makefile will add the rest of the flags.

There's some hand waiving above since it only adds -stdlib=libc++. You should use the CXXFLAGS that Xcode uses to ensure the most trouble-free link. Using different CXXFLAGS has caused a lot of trouble over the years.

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Crypto++ is fat-binary safe (unlike cURL and OpenSSL), so you should be able to perform the following. In fact, our test script tests this class of configurations (Intel and PPC fat binaries, including C++03 through C++17), so it should work out of the box for you:

export CXXFLAGS="-DNDEBUG -g2 -O2 -stdlib=libc++ -arch i386 -arch x86_64"
$ CXX=clang++ make -j 4
$ make -j 4
clang++ -DNDEBUG -g2 -O2 -stdlib=libc++ -arch i386 -arch x86_64 -fPIC -march=native -pipe -c cryptlib.cpp
clang++ -DNDEBUG -g2 -O2 -stdlib=libc++ -arch i386 -arch x86_64 -fPIC -march=native -pipe -c cpu.cpp
clang++ -DNDEBUG -g2 -O2 -stdlib=libc++ -arch i386 -arch x86_64 -fPIC -march=native -pipe -c shacal2.cpp
clang++ -DNDEBUG -g2 -O2 -stdlib=libc++ -arch i386 -arch x86_64 -fPIC -march=native -pipe -c md5.cpp
...

Using both architectures will avoid Undefined symbols for architecture i386 and Undefined symbols for architecture x86_64.

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Here are some related Crypto++ wiki pages, but they are for iOS, and not OS X. They mostly apply, but not exactly.

• IOS (Xcode)
• IOS (Command Line)

Here's a wiki article on building the library from the command line. You're actually hitting the pain point discussed under "Compilers and C++ Runtimes", but its not readily apparent:

• GNUmakefile