cartographer

记录一点小的问题

根据官网要求安装的是gmock官网安装过程，但是make的时候是需要gtest的。
我前几天编译cartographer是能成功的，最近自己在学习gtest，不知道改错了什么，不管怎么编译cartographer都不能成功。

遇到两个问题

1.CMP0026

在下载github上的代码后，直接cmake，因为我的cmake版本是3.5，会有问题。有一个warning就是CMP0026。按照提示步骤上网查了，解决办法如下。
在根目录的CMakeLists.txt文件里添加这句话

cmake_policy(SET CMP0026 OLD)

前几行看起来是这样子的

# Copyright 2016 The Cartographer Authors## Licensed under the Apache License, Version 2.0 (the "License");# you may not use this file except in compliance with the License.# You may obtain a copy of the License at##      http://www.apache.org/licenses/LICENSE-2.0## Unless required by applicable law or agreed to in writing, software# distributed under the License is distributed on an "AS IS" BASIS,# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.# See the License for the specific language governing permissions and# limitations under the License.cmake_minimum_required (VERSION 2.8.7)cmake_policy(SET CMP0026 OLD)project(cartographer)set(CARTOGRAPHER_MAJOR_VERSION 1)set(CARTOGRAPHER_MINOR_VERSION 0)set(CARTOGRAPHER_PATCH_VERSION 0)set(CARTOGRAPHER_VERSION ${CARTOGRAPHER_MAJOR_VERSION}.${CARTOGRAPHER_MINOR_VERSION}.${CARTOGRAPHER_PATCH_VERSION})set(CARTOGRAPHER_SOVERSION ${CARTOGRAPHER_MAJOR_VERSION}.${CARTOGRAPHER_MINOR_VERSION})

之后在cmake是就不会有warning了。

2.gtest编译报错

比较匪夷所思的是在编译cartographer时，需要找到gtest的源码，而且还需要编译。不是可以直接链接到已有的gtest库吗。。
按照教程

sudo apt-get install google-mock

在/usr/src下会出现gmock的目录。但是看了gmock的CMakeLists发现还需要gtest。但是官网给出的步骤里没有gtest的安装。不知道为何。如果不安装，那么编译cartographer时一定会出错。
于是使用

sudo apt-get install libgtest-dev

会发现/usr/src多出了一个gtest文件夹，这样子才是正确的。

然而。。。这样子也不一定可以。反正我这次编译是失败了。
在打开cmake-gui以后去观察了cartographer的配置。其中有一句。
GMOCK_SRC_DIR
默认是会配置成/usr/src/gmock的。然而这样配置，我在编译时会死在%73的进度条上显示

[ 72%] Building CXX object gmock/CMakeFiles/gmock.dir/usr/src/gtest/src/gtest-all.cc.oIn file included from /usr/src/gtest/src/gtest-all.cc:42:0:/usr/src/gtest/src/gtest.cc: In destructor ‘virtual testing::Test::~Test()’:/usr/src/gtest/src/gtest.cc:1897:10: error: type ‘const class testing::internal::scoped_ptr<testing::internal::GTestFlagSaver>’ argument given to ‘delete’, expected pointer   delete gtest_flag_saver_;          ^/usr/src/gtest/src/gtest.cc: At global scope:/usr/src/gtest/src/gtest.cc:2177:1: error: prototype for ‘testing::TestInfo::TestInfo(const string&, const string&, const char*, const char*, testing::internal::TypeId, testing::internal::TestFactoryBase*)’ does not match any in class ‘testing::TestInfo’ TestInfo::TestInfo(const std::string& a_test_case_name, ^In file included from /usr/local/include/gtest/internal/gtest-internal.h:40:0,                 from /usr/local/include/gtest/gtest.h:58,                 from /usr/src/gtest/src/gtest-all.cc:39:/usr/local/include/gtest/gtest.h:772:3: error: candidates are: testing::TestInfo::TestInfo(const testing::TestInfo&)   GTEST_DISALLOW_COPY_AND_ASSIGN_(TestInfo);   ^In file included from /usr/src/gtest/src/gtest-all.cc:39:0:/usr/local/include/gtest/gtest.h:728:3: error:                 testing::TestInfo::TestInfo(const string&, const string&, const char*, const char*, testing::internal::CodeLocation, testing::internal::TypeId, testing::internal::TestFactoryBase*)   TestInfo(const std::string& test_case_name,   ^In file included from /usr/src/gtest/src/gtest-all.cc:42:0:/usr/src/gtest/src/gtest.cc: In function ‘testing::TestInfo* testing::internal::MakeAndRegisterTestInfo(const char*, const char*, const char*, const char*, testing::internal::TypeId, testing::internal::SetUpTestCaseFunc, testing::internal::TearDownTestCaseFunc, testing::internal::TestFactoryBase*)’:/usr/src/gtest/src/gtest.cc:2227:45: error: no matching function for call to ‘testing::TestInfo::TestInfo(const char*&, const char*&, const char*&, const char*&, const void*&, testing::internal::TestFactoryBase*&)’                    fixture_class_id, factory);                                             ^In file included from /usr/local/include/gtest/internal/gtest-internal.h:40:0,                 from /usr/local/include/gtest/gtest.h:58,                 from /usr/src/gtest/src/gtest-all.cc:39:/usr/local/include/gtest/gtest.h:772:3: note: candidate: testing::TestInfo::TestInfo(const testing::TestInfo&)   GTEST_DISALLOW_COPY_AND_ASSIGN_(TestInfo);   ^/usr/local/include/gtest/gtest.h:772:3: note:   candidate expects 1 argument, 6 providedIn file included from /usr/src/gtest/src/gtest-all.cc:39:0:/usr/local/include/gtest/gtest.h:728:3: note: candidate: testing::TestInfo::TestInfo(const string&, const string&, const char*, const char*, testing::internal::CodeLocation, testing::internal::TypeId, testing::internal::TestFactoryBase*)   TestInfo(const std::string& test_case_name,   ^/usr/local/include/gtest/gtest.h:728:3: note:   candidate expects 7 arguments, 6 providedIn file included from /usr/src/gtest/src/gtest-all.cc:42:0:/usr/src/gtest/src/gtest.cc: In function ‘void testing::internal::InitGoogleTestImpl(int*, CharType**)’:/usr/src/gtest/src/gtest.cc:4983:3: error: ‘g_argvs’ was not declared in this scope   g_argvs.clear();   ^In file included from /usr/src/gtest/src/gtest-all.cc:43:0:/usr/src/gtest/src/gtest-death-test.cc: In function ‘void testing::internal::SplitString(const string&, char, std::vector<std::__cxx11::basic_string<char> >*)’:/usr/src/gtest/src/gtest-death-test.cc:1209:60: error: ‘void testing::internal::SplitString(const string&, char, std::vector<std::__cxx11::basic_string<char> >*)’ was declared ‘extern’ and later ‘static’ [-fpermissive]                         ::std::vector< ::std::string>* dest) {                                                            ^In file included from /usr/local/include/gtest/gtest.h:58:0,                 from /usr/src/gtest/src/gtest-all.cc:39:/usr/local/include/gtest/internal/gtest-internal.h:612:6: note: previous declaration of ‘void testing::internal::SplitString(const string&, char, std::vector<std::__cxx11::basic_string<char> >*)’ void SplitString(const ::std::string& str, char delimiter,      ^In file included from /usr/src/gtest/src/gtest-all.cc:45:0:/usr/src/gtest/src/gtest-port.cc: In function ‘const char* testing::internal::StringFromGTestEnv(const char*, const char*)’:/usr/src/gtest/src/gtest-port.cc:798:75: error: ambiguating new declaration of ‘const char* testing::internal::StringFromGTestEnv(const char*, const char*)’ const char* StringFromGTestEnv(const char* flag, const char* default_value) {                                                                           ^In file included from /usr/local/include/gtest/internal/gtest-internal.h:40:0,                 from /usr/local/include/gtest/gtest.h:58,                 from /usr/src/gtest/src/gtest-all.cc:39:/usr/local/include/gtest/internal/gtest-port.h:2555:13: note: old declaration ‘std::__cxx11::string testing::internal::StringFromGTestEnv(const char*, const char*)’ std::string StringFromGTestEnv(const char* flag, const char* default_val);             ^In file included from /usr/src/gtest/src/gtest-all.cc:48:0:/usr/src/gtest/src/gtest-typed-test.cc: In member function ‘const char* testing::internal::TypedTestCasePState::VerifyRegisteredTestNames(const char*, int, const char*)’:/usr/src/gtest/src/gtest-typed-test.cc:71:31: error: ‘defined_test_names_’ was not declared in this scope     for (DefinedTestIter it = defined_test_names_.begin();                               ^/usr/src/gtest/src/gtest-typed-test.cc:88:29: error: ‘defined_test_names_’ was not declared in this scope   for (DefinedTestIter it = defined_test_names_.begin();                             ^gmock/CMakeFiles/gmock.dir/build.make:62: recipe for target 'gmock/CMakeFiles/gmock.dir/usr/src/gtest/src/gtest-all.cc.o' failedmake[2]: *** [gmock/CMakeFiles/gmock.dir/usr/src/gtest/src/gtest-all.cc.o] Error 1CMakeFiles/Makefile2:261: recipe for target 'gmock/CMakeFiles/gmock.dir/all' failedmake[1]: *** [gmock/CMakeFiles/gmock.dir/all] Error 2Makefile:138: recipe for target 'all' failedmake: *** [all] Error 2

解决办法是去github上下载googletest-master。
自己编译一遍。之后在cartographer的CMakeLists.txt里的GMOCK_SRC_DIR为
具体路径按照自己的环境来配置。

/home/xjh/workspace/googletest-master/googlemock

之后编译就能成功了。
我还是不清楚为何cartographer一定要找到gtest的源码，而且还提供编译选项呢。。有知道的求告知~~