链接Matlab生成的C ++库时出现问题

Question

I want to use Code generated from the Matlab C/C++ Coder in my C++ Code.
Matlab creates the Files in the right way, and brings also a Makefile with it, to create a Library. I think, I linked the Library in the right way in my Makefile but it still throws an Error:

/HOMES/~~/testMatlab/main.cpp:11: undefined reference to `emxCreate_real_T(int, int)'

main.cpp:

1 #include<iostream>
2 #include"libMat.h"
3 
4 using namespace std;
5 
6 int main() {
7 double iHeightAll = 100;
8 double iWidthAll = 100;
9 
10 emxArray_real_T *MatlabInput;
11 MatlabInput = emxCreate_real_T((int)iHeightAll,(int)iWidthAll);
12 return 0;
13 }

libMat.h

#ifndef __LIBMAT_H__
#define __LIBMAT_H__
/* Include files */
#include <stddef.h>
#include <stdlib.h>

#include "rtwtypes.h"
#include "libMat_types.h"

/* Function Declarations */
extern emxArray_real_T *emxCreateND_real_T(int numDimensions, int *size);
extern emxArray_real_T *emxCreateWrapperND_real_T(double *data, int numDimensions, int *size);
extern emxArray_real_T *emxCreateWrapper_real_T(double *data, int rows, int cols);
extern emxArray_real_T *emxCreate_real_T(int rows, int cols);
extern void emxDestroyArray_real_T(emxArray_real_T *emxArray);
extern double libMat(const emxArray_real_T *Pic, double height, double width);
extern void libMat_initialize();
extern void libMat_terminate();
#endif

Makefile:

1 CC=g++
2 CFLAGS=  -g
3 OBJECTS= main.o
4 LIBS = -Llibs -lMat
5 
6 # --- targets
7 all:    main
8 main:   $(OBJECTS)
9         $(CC) $(LIBS)  -o main $(OBJECTS)
10         
11 main.o: main.cpp
12         $(CC) $(CFLAGS) -Ilibs -c main.cpp
13 

The Library is located in /libs and is called libMat.a. So that should all be correct

Do I have to call the functions in any other way because they are extern? The file libMat.h is of course implemented in libMat.cpp which is compiled in the linked Library. But I can't change the Code generated by Matlab (libMat etc.)

A problem with 32/64 Bit Stuff can probably be excluded because I build the Library on the same machine as I build my own project.

What is wrong?

Answer 1

Make it

main:   $(OBJECTS)
     $(CC)  -o main $(OBJECTS) $(LIBS) # LIBS at the end

This is a funny thing with ld and static libraries: It only picks those .o files out of the .a that it thinks it needs at that stage in the linking process. If later objects ( main.o in this case) introduce new dependencies, it doesn't go back to look for them in earlier libraries.