1: libpqxx 安装
// 下载库文件 -> 生成共享库（这一步对后面CMakeList 有用）-> 安装
wget http://pqxx.org/download/software/libpqxx/libpqxx-4.0.1.tar.gz
tar -xzvf libpqxx-4.0.1.tar.gz
cd libpqxx-4.0.1
./configure --prefix=/usr/local --enable-shared (这一步很重要，生成共享库 ）
make clean
make
sudo make install

• 验证是否安装成功（查看是否有 libpqxx.so文件）
  cd /usr/local/lib/
  ll | grep libpqxx.so
  或者直接: locate libpqxx.so

2: CMakeLists.txt 调用share 库
cmake_minimum_required(VERSION 3.0.0)
project(test_pgsql VERSION 0.1.0)
add_executable(test_pgsql main.cpp)
target_link_libraries(test_pgsql libpqxx.so )

3: 测试代码

#include <iostream>
#include <pqxx/pqxx>
using namespace std;
using namespace pqxx;
int main(int argc, char* argv[])
{
 try
 {
 connection db(
 "dbname=vslam_map user=postgres password=postgres hostaddr=127.0.0.1 port=5432");

 if (db.is_open())
 {
 cout << "Opened database successfully: " << db.dbname() << endl;
 }
 else
 {
 cout << "Can‘t open database" << endl;
 return 1;
 }
 db.disconnect();
 }
 catch (const std::exception& e)
 {
 cerr << e.what() << std::endl;
 return 1;
 }
}