cpprestsdk: Undefined symbols for architecture x86

问题:

I have visited all the other questions but from what I see none are my issue.

Running OS X El Capitan 10.11.6 on MacBook Pro 16GB memory Intel Core I7

I have ran brew doctor as well but don't see any issues that would cause this issue. Below is my CMakeLists.txt file:

cmake_minimum_required(VERSION 3.0.0)
project(WebClient VERSION 0.0.0)

include(CheckCXXCompilerFlag)
CHECK_CXX_COMPILER_FLAG("-std=c++14" COMPLIER_SUPPORTS_CXX14)
CHECK_CXX_COMPILER_FLAG("-std=c++0x" COMPLIER_SUPPORTS_CXX0X)
if(COMPLIER_SUPPORTS_CXX14)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14")
elseif(COMPILER_SUPPORTS_CXX0X)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")
else()
    message(STATUS "The compiler ${CMAKE_CXX_COMPILER} has no C++14 support.
                    Please use a different C++ compiler.")
endif()

FIND_PACKAGE( Boost 1.62 COMPONENTS program_options REQUIRED )
INCLUDE_DIRECTORIES( ${Boost_INCLUDE_DIR} )

set(OPT_CPPFLAGS "-I/usr/local/opt/openssl/include -I/usr/local/opt/libiconv/include")
set(OPT_LDFLAGS "-v -lcpprest -lboost_system -L/usr/local/opt/openssl/lib -L/usr/local/opt/libiconv/lib -lcrypto -lssl")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OPT_CPPFLAGS} -v -g -O3 -fno-common -stdlib=libc++")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${OPT_LDFLAGS}")

add_executable(anyExecutable webclient.cpp)

TARGET_LINK_LIBRARIES( anyExecutable ${Boost_LIBRARIES} )

include(CPack)

I used brew to install cpprestsdk/2.8.0 which also includes boost/1.62.0 and openssl/1.0.2j and libiconv/1.14. My code is from a tutorial on wiki cpprestsdk.

#include <cpprest/http_client.h>
#include <cpprest/filestream.h>
#include <atomic>

using namespace utility;                    // Common utilities like string conversions
using namespace web;                        // Common features like URIs.
using namespace web::http;                  // Common HTTP functionality
using namespace web::http::client;          // HTTP client features
using namespace concurrency::streams;       // Asynchronous streams

int main(int argc, char* argv[]) {
  auto fileStream = std::make_shared<ostream>();

  // Open stream to output file.
  pplx::task<void> requestTask = fstream::open_ostream( U("results.xml") ).then(
    [=](ostream outFile) {
        *fileStream = outFile;

        // Create http_client to send the request.
        http_client client(U("http://www.dictionaryapi.com/api/v1/references/"));

        // Build request URI and start the request.
        uri_builder builder(U("thesaurus/xml/"));
        builder.append_path(U("ranking"),true);
        builder.append_query(U("?key"), U("--------------------"));
        return client.request(methods::GET, builder.to_string());
  })

  // Handle response headers arriving.
  .then( [=](http_response response ) {
    printf("Received response status code:%u\n", response.status_code());

    // Write response body into the file.
    return response.body().read_to_end(fileStream->streambuf());
  })

  // Close the file stream.
  .then( [=](size_t ) {
    return fileStream->close();
  });

  // Wait for all the outstanding I/O to complete and handle any exceptions
  try {
    requestTask.wait();
  } catch (const std::exception &e) {
    printf("Error exception:%s\n", e.what());
  }//try-catch BLOCK

  return 0;
}//Main

To save some space only printing some the errors they all the same in can't be found:

    [vscode] Executing cmake command: cmake --build /Users/gumpy/git-repos/webapi/build --target all --config Debug -- -j 10
[ 50%] Building CXX object CMakeFiles/anyExecutable.dir/webclient.cpp.o
Apple LLVM version 8.0.0 (clang-800.0.38)
Target: x86_64-apple-darwin15.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
 "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang" -cc1 -triple x86_64-apple-macosx10.11.0 -Wdeprecated-objc-isa-usage -Werror=deprecated-objc-isa-usage -emit-obj -disable-free -disable-llvm-verifier -discard-value-names -main-file-name webclient.cpp -mrelocation-model pic -pic-level 2 -mthread-model posix -mdisable-fp-elim -masm-verbose -munwind-tables -target-cpu core2 -target-linker-version 274.1 -v -dwarf-column-info -debug-info-kind=standalone -dwarf-version=2 -debugger-tuning=lldb -coverage-file /Users/gumpy/git-repos/webapi/build/CMakeFiles/anyExecutable.dir/webclient.cpp.o -resource-dir /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/8.0.0 -I /usr/local/include -I /usr/local/opt/openssl/include -I /usr/local/opt/libiconv/include -stdlib=libc++ -O3 -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /Users/gumpy/git-repos/webapi/build -ferror-limit 19 -fmessage-length 0 -stack-protector 1 -fblocks -fobjc-runtime=macosx-10.11.0 -fencode-extended-block-signature -fcxx-exceptions -fexceptions -fmax-type-align=16 -fno-common -fdiagnostics-show-option -vectorize-loops -vectorize-slp -o CMakeFiles/anyExecutable.dir/webclient.cpp.o -x c++ /Users/gumpy/git-repos/webapi/webclient.cpp
clang -cc1 version 8.0.0 (clang-800.0.38) default target x86_64-apple-darwin15.6.0
ignoring nonexistent directory "/usr/include/c++/v1"
ignoring duplicate directory "/usr/local/include"
  as it is a non-system directory that duplicates a system directory
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/opt/openssl/include
 /usr/local/opt/libiconv/include
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1
 /usr/local/include
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/8.0.0/include
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include
 /usr/include
 /System/Library/Frameworks (framework directory)
 /Library/Frameworks (framework directory)
End of search list.
[100%] Linking CXX executable anyExecutable
Apple LLVM version 8.0.0 (clang-800.0.38)
Target: x86_64-apple-darwin15.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
 "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld" -demangle -dynamic -arch x86_64 -macosx_version_min 10.11.0 -o anyExecutable -L/usr/local/opt/openssl/lib -L/usr/local/opt/libiconv/lib -search_paths_first -headerpad_max_install_names -lcpprest -lboost_system -lcrypto -lssl CMakeFiles/anyExecutable.dir/webclient.cpp.o /usr/local/lib/libboost_program_options-mt.dylib -lc++ -lSystem /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/8.0.0/lib/darwin/libclang_rt.osx.a
Undefined symbols for architecture x86_64:
  "boost::this_thread::interruption_point()", referenced from:
      boost::condition_variable::wait(boost::unique_lock<boost::mutex>&) in webclient.cpp.o
      boost::condition_variable::do_wait_until(boost::unique_lock<boost::mutex>&, timespec const&) in webclient.cpp.o
  "boost::chrono::steady_clock::now()", referenced from:
      pplx::details::event_impl::wait(unsigned int) in webclient.cpp.o
  "boost::chrono::system_clock::now()", referenced from:
      pplx::details::event_impl::wait(unsigned int) in webclient.cpp.o
  "boost::detail::get_current_thread_data()", referenced from:
      boost::detail::interruption_checker::interruption_checker(_opaque_pthread_mutex_t*, _opaque_pthread_cond_t*) in webclient.cpp.o
ld: symbol(s) not found for architecture x86_64

回答1:

The missing symbol names was due to a missing library. The necessary CPPFLAGS and LDFLAGS are:

CPPFLAGS = -stdlib=libc++
LDFLAGS = -lcpprest -lboost_system -lboost_thread-mt -lboost_chrono-mt -lssl -lcrypto

Thanks so much for everyone's help.

回答2:

Original Question:

  "web::uri_builder::append_path(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool)", referenced from:
      std::__1::__function::__func<main::$_0, std::__1::allocator<main::$_0>, pplx::task<web::http::http_response> (Concurrency::streams::basic_ostream<unsigned char>)>::operator()(Concurrency::streams::basic_ostream<unsigned char>&&) in webclient.cpp.o
  "web::uri_builder::append_query(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool)", referenced from:
      web::uri_builder& web::uri_builder::append_query<char [37]>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, char const (&) [37], bool) in webclient.cpp.o
  "web::uri_builder::to_string()", referenced from:
      std::__1::__function::__func<main::$_0, std::__1::allocator<main::$_0>, pplx::task<web::http::http_response> (Concurrency::streams::basic_ostream<unsigned char>)>::operator()(Concurrency::streams::basic_ostream<unsigned char>&&) in webclient.cpp.o
  "web::uri::encode_impl(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::function<bool (int)> const&)", referenced from:
      web::uri_builder& web::uri_builder::append_query<char [37]>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, char const (&) [37], bool) in webclient.cpp.o
  ...

The ::__1 is LLVM's anonymous namespace. What you see above is a symptom of mixing and matching runtimes. I.e., inconsistent use of -stdlib=XXX.

You need to build everything with GNU's gear and -stlib=libstdc++; or you need to build everything with LLVM's gear and -stdlib=libc++.

What I found works best to avoid user problems and questions is to always use LLVM's gear on OS X and iOS. I.e., always use -stdlib=libc++.

---

Updated Question:

Undefined symbols for architecture x86_64:
  "boost::this_thread::interruption_point()", referenced from:
      boost::condition_variable::wait(boost::unique_lock<boost::mutex>&) in webclient.cpp.o
      boost::condition_variable::do_wait_until(boost::unique_lock<boost::mutex>&, timespec const&) in webclient.cpp.o
  "boost::chrono::steady_clock::now()", referenced from:
      pplx::details::event_impl::wait(unsigned int) in webclient.cpp.o
  "boost::chrono::system_clock::now()", referenced from:
      pplx::details::event_impl::wait(unsigned int) in webclient.cpp.o
  "boost::detail::get_current_thread_data()", referenced from:
      boost::detail::interruption_checker::interruption_checker(_opaque_pthread_mutex_t*, _opaque_pthread_cond_t*) in webclient.cpp.o
ld: symbol(s) not found for architecture x86_64

For the updated question, see Using and building the library in the Boost user guide. You have to build Boost with threading support (does Brew do that?), and you have to link to the Boost threading library (is CMake doing that?).

I don't use Boost or CMake, so I can't take you any further. Sorry about that.

---

set(OPT_CPPFLAGS "-I/usr/local/opt/openssl/include -I/usr/local/opt/libiconv/include")

I'm no CMake expert, but this could be problematic, too. CPPFLAGS is the flags for the C preprocessor. They may or may not be added to the CFLAGS and CXXFLAGS.

You should definitely call-out the same flags for CFLAGS and CXXFLAGS just in case. If this were an Autotools project, then I would change the should to a must. But like I said, I'm no CMake expert by any strecth of the imagination.

---

And one final note... You can't use CMake to build OpenSSL. You have to configure an build it yourself. Once installed, you can reference the installed OpenSSL in a find-openssl.cmake type fashion.

The reasons are not readily apprent... OpenSSL's Configure script sets up some important settings that are used later in the build process. The two most important files for the settings are <opensslconf.h> and <bn.h>.

You can also get an impressive speed improvement (2x to 4x) for Diffie-Hellman and Elliptic Curves on Intel-based x86_64 machines by Configureing with enable-ec_nistp_64_gcc_128.

回答3:

It looks like this may be the same issue you have, with the answer being link against -lcrypto.

Edit: Your problem is that you're trying to build a program that needs to be linked against other "libraries" - that is, other pieces of code that are usually pre-compiled - that are somewhere on your system, and which define "symbols," which is basically another way of saying variables or function names.

You let the compiler know which libraries you need by including arguments to the compile command that signify what you need to be linked with - in this case, your first few issues went away because you linked with -lcrypto, and from then on your code was able to find the 'symbols' - that is, variables and function names - that were previously 'undefined.'

For the rest of your issues, where you added 'lcrypto,' try using the arguments from this wiki on building cpprestsdk on Linux. The flags appear to be:

-lboost_system -lssl -lcpprest -lboost_chrono

Last, but not least, have you follow the instructions for building this software on mac OSX on their site? It might save you a lot of pain! :)

Edit: added a few more.