CentOS7系统上的GPSTK源码安装

网址：http://www.gpstk.org/bin/view/Documentation/BuildingGPSTkUnderUnix

这里使用Cmake来安装源码，网站上的原文摘抄如下，有少部分作了修改的地方，使用红色字体和下划线来标识。

The following procedure will build and install the GPSTk.

1. Ensure that prerequisites such as CMake have been installed.
2. Download the GPSTk source distribution.
3. Extract the GPSTk tarball. For example, using GNU tar

   tar xvzf gpstk.tar.gz

4. Create a directory for your build. For example, change into the gpstk/directory and type

   mkdir build

5. Change into the gpstk/build directory, this will be where all of the build files will reside.
6. If GPSTk Core will be installed as a system library in /usr/local, execute the following commands:

   cmake ../dev
   make

   To install to a different directory, the install directory must be set-up when CMake configures the makefiles, add the following command:

   -DCMAKE_INSTALL_PREFIX:PATH=/path/to/install

   To build GPSTk with Ext, in addition to Core, add the following command:

   -DBUILD_EXT=ON

   To turn on processing of python extension package, add the following command:

   -DBUILD_PYTHON=ON

   To turn on test mode, add the following command:

   -DTEST_SWITCH=ON

   Example - Command for building GPSTk with core, ext, python, and test code and installing to sytem library in /usr/local:

   [She@she-centos7 gpstk-2.5.src]$ sudo mkdir /opt/gpstk-2.5.linux.x86_64
   [She@she-centos7 gpstk-2.5.src]$ cd build
   [She@she-centos7 build]$ cmake -DBUILD_EXT=ON -DBUILD_PYTHON=ON -DTEST_SWITCH=ON ../dev
   -- The C compiler identification is GNU 4.8.5
   -- The CXX compiler identification is GNU 4.8.5
   -- Check for working C compiler: /usr/bin/cc
   -- Check for working C compiler: /usr/bin/cc -- works
   -- Detecting C compiler ABI info
   -- Detecting C compiler ABI info - done
   -- Check for working CXX compiler: /usr/bin/c++
   -- Check for working CXX compiler: /usr/bin/c++ -- works
   -- Detecting CXX compiler ABI info
   -- Detecting CXX compiler ABI info - done
   system = Linux-3.10.0-514.16.1.el7.x86_64
   system_name = Linux
   Notice: Will install GPSTk to the path /opt/gpstk-2.5.linux.x86_64
   -- Configuring done
   -- Generating done
   CMake Warning:
     Manually-specified variables were not used by the project:
   
       BUILD_EXT
       BUILD_PYTHON
   
   -- Build files have been written to: /home/She/Downloads/GPSTK/gpstk-2.5.src/build

7. To install GPSTk, execute

   sudo make install

8. To test GPSTk (if Test_Switch=ON), execute

   sudo make test

9. To build the source documentation using doxygen: Change into the gpstk/dev directory (if using Developer repo) or the gpstk/directory (if using the tarball), and type

   doxygen

接下来，选择 GPSTK 网站提供的例一作为测试对象，看程序的功能是否可用。

编译文件 Makefile 内容如下：

PROGRAM    = example
RM         = rm -f
CC         = g++

SOURCES  = example1.cpp
OBJECTS = ${SOURCES:%.cpp=%.o}

LIBPATH += -L/usr/local/lib

LIBS    =  -lgpstk

all:    ${PROGRAM}

${PROGRAM}: ${SOURCES} ${OBJECTS}
    ${CC} -o ${PROGRAM} ${LIBPATH}  ${OBJECTS} ${LIBS}

clean:
    ${RM} ${OBJECTS} ${PROGRAM}

编译可以正常通过，但是运行时总是报错，提示

$ make -o example -L/usr/local/lib -lgpstk example1.cpp
$ ./example

error while loading shared libraries: libgpstk.so: cannot open shared object file: No such file or directory

经查，这个文件/usr/local/lib/libgpstk.so，确实存在，那么，就是默认搜索时找不到这个路径。

为了解决这个bug，我们将这个文件映射到默认搜索路径/usr/lib下：

$ sudo ln -s /usr/local/lib/libgpstk.so /usr/lib/libgpstk.so

再重新编译和运行程序，就一切正常了：

$ make clean
$ make
$ ./example
Hello world!
   The current civil time is 06/07/2017 07:16:53 UTC
   The current year is 2017
   The current day of year is 158
   The current second of day is 26213.5
   The current full GPS week is 1952
   The current short GPS week is 928
   The current day of GPS week is 3
   The current second of GPS week is 285414
   The current Modified Julian Date is 57911.303397479 UTC

如果添加软链接之后仍不奏效，则添加环境变量，使它在运行时能搜索到相应的库文件： $ sudo vi /etc/profile.d/GPSTKsetvar.sh ，添加以下内容：

# setting environment variables for GPSTK, edit by She
export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/usr/local/lib:/usr/lib

并更新环境变量： source /etc/profile.d/GPSTKsetvar.sh 。

再次编译并运行，即可得到正确的运行结果。