linux c++ 怎么 调用自己函数的

实验平台：ubuntu 12.04 + g++4.6 + matlab2012a

问题描述：
有一个c++程序main.cpp，和一个matlab函数myFunc.m。现在要做这件事：
1）从main.cpp中传递2个double类型的数值a和b到myFunc.m中
2）myFunc.m中求和（sum = a+b）
3）main.cpp中接收myFunc.m返回的和并输出。

思路：
1）设置matlab的编译器，使用gcc编译器。编译m文件成.so。
2）编译.cpp文件，编译时调用.so库（添加.so的路径到编译选项）。

步骤：
1）将自己的matlab函数（myFunc.m）编译成动态链接库

(1) 设定编译器为gcc，在matlab 命令行依次执行命令mex -setup和mbuild -setup：
>> mex -setup Options files control which compiler to use, the compiler and link command options, and the runtime libraries to link against. Using the 'mex -setup' command selects an options file that is placed in ~/.matlab/R2012a and used by default for 'mex'. An options file in the current working directory or specified on the command line overrides the default options file in ~/.matlab/R2012a. To override the default options file, use the 'mex -f' command (see 'mex -help' for more information).The options files available for mex are: 1: /opt/MATLAB/R2012a/bin/mexopts.sh : Template Options file for building gcc MEX-files 0: Exit with no changesEnter the number of the compiler (0-1):1/opt/MATLAB/R2012a/bin/mexopts.sh is being copied to ~/.matlab/R2012a/mexopts.shcp: cannot create regular file `~/.matlab/R2012a/mexopts.sh': Permission denied************************************************************************** Warning: The MATLAB C and Fortran API has changed to support MATLAB variables with more than 2^32-1 elements. In the near future you will be required to update your code to utilize the new API. You can find more information about this at: http://www.mathworks.com/help/techdoc/matlab_external/bsflnue-1.html Building with the -largeArrayDims option enables the new API. **************************************************************************>> mbuild -setup Options files control which compiler to use, the compiler and link command options, and the runtime libraries to link against. Using the 'mbuild -setup' command selects an options file that is placed in ~/.matlab/R2012a and used by default for 'mbuild'. An options file in the current working directory or specified on the command line overrides the default options file in ~/.matlab/R2012a. To override the default options file, use the 'mbuild -f' command (see 'mbuild -help' for more information).The options files available for mbuild are: 1: /opt/MATLAB/R2012a/bin/mbuildopts.sh : Build and link with MATLAB Compiler generated library via the system ANSI C/C++ compiler 0: Exit with no changesEnter the number of the compiler (0-1):1/opt/MATLAB/R2012a/bin/mbuildopts.sh is being copied to ~/.matlab/R2012a/mbuildopts.shcp: cannot create regular file `~/.matlab/R2012a/mbuildopts.sh': Permission denied>>

(2) 在matlab中，编写myFunc.m文件内容如下：
function [ C ] = myFunc(A, B)C = A+B;end

(3) 生成myFunc.m的动态链接库（.so）
>> mcc -W cpplib:libmyFunc -T link:lib myFunc.m -cWarning: MATLAB Toolbox Path Cache is out of date and is not being used.Type 'help toolbox_path_cache' for more info >>

等待数秒，完成。可以看到myFunc.m所在的目录下生成了多个文件：
$ lslibmyFunc.cpp libmyFunc.ctf libmyFunc.exports libmyFunc.h libmyFunc.so main.cpp mccExcludedFiles.log myFunc.m readme.txt

命
令解释：其中-W是控制编译之后的封装格式；cpplib是指编译成C++的lib；cpplib冒号后面是指编译的库的名字；-T表示目
标，link:lib表示要连接到一个库文件的目标，目标的名字即是.m函数的名字。-c表明需要生成.ctf文件，比如本例如果不加-c就不会生成
“libmyFunc.ctf”。

生成的文件中打开“libmyFunc.h”可以看到一行：
extern LIB_libmyFunc_CPP_API void MW_CALL_CONV myFunc(int nargout, mwArray& C, const mwArray& A, const mwArray& B);
这
个就是我们的myFunc.c函数待会儿在c++中调用时的接口。有4个参数，第一个是参数个数，第二个是用来接收函数返回值的，后面2个是从c++中传
递进来的变量。我们还会用到“libmyFunc.h”中的另外2个函数：libmyFuncInitialize()初始化，和注销
libmyFuncTerminate()。

2）编写main.cpp，代码如下：
#include #include "mclmcr.h"#include "matrix.h"#include "mclcppclass.h"#include "libmyFunc.h"#include "mclmcrrt.h"using namespace std;int main() { // initialize lib，这里必须做初始化！ if( !libmyFuncInitialize()) { std::cout << "Could not initialize libmyFunc!" << std::endl; return -1; } // 用户输入2个数值 double a, b; cout<<"Please input 2 numbers and then press enter: "<> a; cin >> b; double c; //used to receive the result // 为变量分配内存空间, maltab只有一种变量，就是矩阵，为了和c++变量接轨，设置成1*1的矩阵 mwArray mwA(1, 1, mxDOUBLE_CLASS); //1,1表示矩阵的大小, mxDOUBLE_CLASS表示变量的精度 mwArray mwB(1, 1, mxDOUBLE_CLASS); mwArray mwC(1, 1, mxDOUBLE_CLASS); // 调用类里面的SetData函数给类赋值 mwA.SetData(&a, 1); mwB.SetData(&b, 1); // 调用自己的函数，求和。 myFunc(1, mwC, mwA, mwB); c = mwC.Get(1, 1); cout<<"The sum is: "<
3）编译main.cpp函数，调用libmyFunc.so
$ g++ -o main -I. -I/opt/MATLAB/R2012a/extern/include -L. -L/opt/MATLAB/R2012a/runtime/glnxa64 main.cpp -lmyFunc -lm -lmwmclmcrrt -lmwmclmcr

开始编译时也遇到一些问题，主要是链接库路径问题导致的编译错误，详细错误汇总在另篇笔记里（点此查看）。
编译成功后，需要装一下MCR Installer，步骤点此。

运行结果：
$ ./main Warning: latest version of matlab app-defaults file not found.Contact your system administrator to have this file installedPlease input 2 numbers and then press enter: 10 100The sum is: 110$ ./main Warning: latest version of matlab app-defaults file not found.Contact your system administrator to have this file installedPlease input 2 numbers and then press enter: 1 1The sum is: 2

源代码及编译过程中的所有文件已打包，点击这里可以下载。