之前在这里和这里调用了matlab自带的一些函数,是通过matlab引擎来实现的。那里调用的是matlab自带的函数,那么如果想调用自己写的.m函数该怎么办呢?其实很简单,原理类似,方法也不止一种。这篇笔记我先尝试通过mcc将.m函数编译成动态链接库供c++调用的方式。在另一篇笔记中还尝试了另一种途径:通过matlab引擎来实现。其实,调用自己编写的m函数,只是多了一步将自己的matlab函数编译成动态链接库文件(也就类似自带的那种eigen.h和libeng.so)。这里练习了一个小例子,展示从c++中调用matlab里面的自己写的函数。
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 changes
-
- Enter the number of the compiler (0-1):
- 1
-
-
- /opt/MATLAB/R2012a/bin/mexopts.sh is being copied to ~/.matlab/R2012a/mexopts.sh
-
- cp: 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 changes
-
- Enter the number of the compiler (0-1):
- 1
-
-
- /opt/MATLAB/R2012a/bin/mbuildopts.sh is being copied to ~/.matlab/R2012a/mbuildopts.sh
-
- cp: 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 -c
- Warning: 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:
- $ ls
- libmyFunc.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 <iostream>
- #include "mclmcr.h"
- #include "matrix.h"
- #include "mclcppclass.h"
- #include "libmyFunc.h"
- #include "mclmcrrt.h"
-
- using namespace std;
-
- int main() {
-
-
- if( !libmyFuncInitialize())
- {
- std::cout << "Could not initialize libmyFunc!" << std::endl;
- return -1;
- }
-
-
- double a, b;
- cout<<"Please input 2 numbers <a b> and then press enter: "<<endl;
- cin >> a;
- cin >> b;
-
- double c;
-
-
- mwArray mwA(1, 1, mxDOUBLE_CLASS);
- mwArray mwB(1, 1, mxDOUBLE_CLASS);
- mwArray mwC(1, 1, mxDOUBLE_CLASS);
-
-
- mwA.SetData(&a, 1);
- mwB.SetData(&b, 1);
-
-
- myFunc(1, mwC, mwA, mwB);
-
- c = mwC.Get(1, 1);
-
- cout<<"The sum is: "<<c<<endl;
-
-
-
- libmyFuncTerminate();
-
-
- mclTerminateApplication();
-
-
- return EXIT_SUCCESS;
- }
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 installed
- Please input 2 numbers <a b> and then press enter:
- 10 100
- The sum is: 110
-
- $ ./main
- Warning: latest version of matlab app-defaults file not found.
- Contact your system administrator to have this file installed
- Please input 2 numbers <a b> and then press enter:
- 1 1
- The 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。
参考:
http://www.oschina.net/question/565065_72598
http://blog.csdn.net/ylf13/article/details/20005347
http://developer.51cto.com/art/200909/150944.htm
http://www.cnblogs.com/xkfz007/archive/2012/02/02/2336298.html
http://www.cnblogs.com/tiandsp/archive/2013/02/26/2934070.html
http://blog.sciencenet.cn/blog-620659-579845.html
http://blog.csdn.net/nupt123456789/article/details/7463612
http://stackoverflow.com/questions/3165080/how-to-call-matlab-from-c-code