library linking problem

Dear Friends,
I am having problems with linking my *.cc file with another library file. I have asigned the path in the Makefile but its not working and giving errors while doing 'make'. I am a newbee in C++ programing and am trying to modify a program written by somebody else. Kindly help me in debugging.

Thanks in advance.
Sankar

This is the Makefile and below is the error message
Makefile :-

FFTWDIR = /scratch/tmp1/tmp/calphy/KER_05082005/fftw
CPPFLAGS += -I$(FFTWDIR)/include -Wall -fPIC
LDFLAGS += -L$(FFTWDIR)/lib -lmffm -lfft -l2Dfft -lfftw3

all: find_instr

instr: instr.cc
g++ $(CPPFLAGS) -O3 -o $@ $^ $(LDFLAGS)

find_instr: find_instr.cc
g++ $(CPPFLAGS) -O3 -o $@ $^ $(LDFLAGS)


clean:
rm -f a.out cfft instr


ERROR MESSAGE :-

[calphy@lin07 analysis]$ make
g++ -I/scratch/tmp1/tmp/calphy/KER_05082005/fftw/include -Wall -fPIC -O3 -o find_instr find_instr.cc -L/scratch/tmp1/tmp/calphy/KER_05082005/fftw/lib -lmffm -lfft -l2Dfft -lfftw3
/tmp/ccXeD1pe.o(.text+0x889): In function `main':
: undefined reference to `complexFFTData::complexFFTData[in-charge](int)'
/tmp/ccXeD1pe.o(.text+0x8a3): In function `main':
: undefined reference to `complexFFT::complexFFT[in-charge](complexFFTData*)'
/tmp/ccXeD1pe.o(.text+0x8bd): In function `main':
: undefined reference to `complexFFTData::complexFFTData[in-charge](int)'
/tmp/ccXeD1pe.o(.text+0x8d7): In function `main':
: undefined reference to `complexFFT::complexFFT[in-charge](complexFFTData*)'
/tmp/ccXeD1pe.o(.text+0x8f1): In function `main':
: undefined reference to `complexFFTData::complexFFTData[in-charge](int)'
/tmp/ccXeD1pe.o(.text+0x90b): In function `main':
: undefined reference to `complexFFT::complexFFT[in-charge](complexFFTData*)'
/tmp/ccXeD1pe.o(.text+0xa82): In function `main':
: undefined reference to `complexFFT::fwdTransform()'
/tmp/ccXeD1pe.o(.text+0xa8e): In function `main':
: undefined reference to `complexFFT::fwdTransform()'
/tmp/ccXeD1pe.o(.text+0xb30): In function `main':
: undefined reference to `complexFFT::invTransform()'
/tmp/ccXeD1pe.o(.text+0xcf1): In function `main':
: undefined reference to `complexFFT::~complexFFT [in-charge]()'
/tmp/ccXeD1pe.o(.text+0xcfd): In function `main':
: undefined reference to `complexFFTData::~complexFFTData [in-charge]()'
/tmp/ccXeD1pe.o(.text+0xd09): In function `main':
: undefined reference to `complexFFT::~complexFFT [in-charge]()'
/tmp/ccXeD1pe.o(.text+0xd15): In function `main':
: undefined reference to `complexFFTData::~complexFFTData [in-charge]()'
/tmp/ccXeD1pe.o(.text+0xd21): In function `main':
: undefined reference to `complexFFT::~complexFFT [in-charge]()'
/tmp/ccXeD1pe.o(.text+0xd2d): In function `main':
: undefined reference to `complexFFTData::~complexFFTData [in-charge]()'
/tmp/ccXeD1pe.o(.text+0x1a88): In function `main':
: undefined reference to `complexFFT::~complexFFT [in-charge]()'
/tmp/ccXeD1pe.o(.text+0x1a99): In function `main':
: undefined reference to `complexFFTData::~complexFFTData [in-charge]()'
/tmp/ccXeD1pe.o(.text+0x1aaa): In function `main':
: undefined reference to `complexFFT::~complexFFT [in-charge]()'
/tmp/ccXeD1pe.o(.text+0x1abb): In function `main':
: undefined reference to `complexFFTData::~complexFFTData [in-charge]()'
/tmp/ccXeD1pe.o(.text+0x1acc): In function `main':
: undefined reference to `complexFFT::~complexFFT [in-charge]()'
/tmp/ccXeD1pe.o(.text+0x1add): In function `main':
: undefined reference to `complexFFTData::~complexFFTData [in-charge]()'
collect2: ld returned 1 exit status
make: *** [find_instr] Error 1

It looks like the linkage type of certain identifiers in your program is wrong. Check the relevant library's header file and see whether it contains an
extern "C"
{

//..declarations

}

declaration. Make sure that the function protypes you're using in yoru program are in sync with how they are defined in the library. In other words, I suspect that your program's headers don't have this extern "C" declaration.

Dear Danny,
I didn't find anything like 'extern "C" declaration' or may be I didn't understand what you said. I actually have an experimental spectrum. I want to find out the true spectrum by deconvolution method using an instrumentation function. So I am using the FFT. I am sending you the main 'find_instr.cc' file and complexFFT.H. They are quite big. I think they will be helpful.

Thanks,
Sankar

complexFFT.H :-

/* Copyright 2001,2002 Matt Flax <flatmax@ieee.org>
This file is part of the MFFM FFTw Wrapper library.

MFFM MFFM FFTw Wrapper library is free software; you can
redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

MFFM FFTw Wrapper library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You have received a copy of the GNU General Public License
along with the MFFM FFTw Wrapper library
*/
#ifndef COMPLEXFFT_H_
#define COMPLEXFFT_H_

#include <fftw3.h>

#ifndef fftw_real
#define fftw_real double
#endif
#define c_re(c) ((c)[0])
#define c_im(c) ((c)[1])

#include <iomanip>
using namespace std;

#define PLANTYPE FFTW_ESTIMATE

/// class complexFFTData controls and manipulates complex fft data
class complexFFTData {
public:
/// Specifies the size of the data array
int size;
/// the input and output arrays
fftw_complex *in, *out;
/// the power_spectrum array
fftw_real *power_spectrum;
/// The total power (summed) of the power spectrum as used in the method compPowerSpec
double totalPower;

/// Constructor with all memory to be allocated internally
complexFFTData(int sz);
/// Deconstructor
~complexFFTData(void);

/// Use this to change associated fft data (for fft'ing)
void switchData(complexFFTData *d);

/// Limits the maximum to 'lim' and returns the last fft bin with max
int limitHalfPowerSpec(double lim);

/// Returns the number of elements in the input and output arrays
int getSize(){return size;}
// int getHalfSize(){ if (!(size%2)) return size/2; else return size/2+1;}

/// This function computes the power spectrum and returns the max bin
int compPowerSpec();
// int powerSpecDeriv(); // Find the derivative of the power spectrum
};

///class complexFFT controls fftw plans and executes fwd/inv transforms
class complexFFT {
/// The fwd/inv plans
fftw_plan fwdPlan, invPlan;
/// Method to create the plans
void createPlan(void);
/// Method to destroy the plans
void destroyPlan(void);
protected:
// int size;
/// The pointer to the relevant data
complexFFTData *data;
public:

// complexFFT(int sz, char *ws=NULL);
/// fft init ... data pointed to by 'd'
complexFFT(complexFFTData *d);
/// fft deconstructor
~complexFFT();

/// Use this to change associated fft data (for fft'ing)
void switchData(complexFFTData *d);

/// Forward transform the data (in to out)
void fwdTransform(); // Forward fft
/// Inverse transform the data (out to in)
void invTransform(); // Inverse fft
};
/** \example complexFFTExample.cc
* This is an example of how to use the class.
*/
#endif // COMPLEXFFT_H_

find_instr.cc :-

// Given spectrum and simulation find instrumentation function


#include <fstream>
#include <iomanip>
#include <iostream>

//#include <realFFT.H>
#include "complexFFT.H"
#include <stdlib.h>
#define SPECFILE "Ar2+_pure_expt_norm_spec.dat"
#define SIMFILE "Ar2+_sim_norm_spec.dat"
#define OUTPUTFILE "instr_pow.dat"
#define OUTPUTFILE1 "instr_real.txt"
#define OUTPUTFILE2 "instr_imag.txt"

int main (void){
ifstream spectrum(SPECFILE);
ifstream simulation(SIMFILE);
ofstream output(OUTPUTFILE);
ofstream output1(OUTPUTFILE1);
ofstream output2(OUTPUTFILE2);

int count_spec=0, count_sim=0;
double var;
double x,y,u,v, x1,y1, temp;

// Get the file size and check file exists ....
if (!spectrum){
cout <<"input spectrum not opened !"<<endl;
exit(-1);
}
if (!simulation){
cout <<"input simulation not opened !"<<endl;
exit(-1);
}

while (spectrum >> var)
count_spec++;

while (simulation >> var)
count_sim++;


cout<<count_spec<<" variables in file "<<SPECFILE<<endl;
cout<<count_sim <<" variables in file "<<SIMFILE<<endl;

if(count_spec!=count_sim) {
cout<< "Unequal input files !"<< endl;
exit(-1);
}


spectrum.clear();
spectrum.seekg(0);

simulation.clear();
simulation.seekg(0);

// realFFTData fftData(count);
// realFFT rfft(&fftData);

complexFFTData specData(count_spec);
complexFFT specfft(&specData);

complexFFTData simData(count_sim);
complexFFT simfft(&simData);

complexFFTData outData(count_spec);
complexFFT outfft(&outData);

// read data into data and rdata :
for (int i=0; i<count_spec; i++){
spectrum >> c_re(specData.in[i]);
c_im(specData.in[i])=0;
}
spectrum.close();

for(int i=0;i<count_sim;i++){
simulation >> c_re(simData.in[i]);
c_im(simData.in[i])=0;
}
simulation.close();


// forward transform :
specfft.fwdTransform();
//
//instfft.fwdTransform();
simfft.fwdTransform();

for(int i=0;i<count_sim;i++){
x= c_re(specData.out[i]);
y= c_im(specData.out[i]);
u= c_re(simData.out[i]);
v= c_im(simData.out[i]);

temp= u*u+v*v;
x1 = (x*u+y*v)/temp;
y1 = (y*u-x*v)/temp;

c_re(outData.in[i]) = x1;
c_im(outData.in[i]) = y1;
}
//inverse transform
//outfft.invTransform();





// Find the power spectrum ...
//fftData.compPowerSpec();

// inverse transform to check what happens (have to rescale too):
outfft.invTransform();

// output to file :
//for (int i=0; i<(count+1)/2; i++){
// output << fftData.power_spectrum[i]<<'\n';
//}
// cout <<(count+1)/2<<endl;
//output.close();

for (int i=0; i<count_sim; i++){
output1 << c_re(outData.in[i]) <<'\n';
output2 << c_im(outData.in[i]) <<'\n';

output << c_re(outData.out[i]) << " " << c_im(outData.out[i]) << endl;
}
output.close();
output1.close();
output2.close();
return 0;
}

OK, so it's not an extern "C" problem. The problem is simpler: the linker doesn't find the definitions of the member functions you're calling. The most liekly cause is that the linker doesn't look for it in the right places.

Dear Danny,
I have my complexFFT.H file in the include directory whose path I am defining in the Makefile for find_instr.cc to link to the required header files but still its showing me errors. So where I am wrong.

Regards,
Sankar


[calphy@lin07 include]$ ls
complexFFT.H fftw3.f fftw3.h real2DFFT.H realFFTData.H realFFT.H
[calphy@lin07 include]$ pwd
/scratch/tmp1/tmp/calphy/KER_05082005/fftw/include
[calphy@lin07 include]$

The erros you're getting are generated by the linker. This means that the ld command probably doesn't contain the correct libraries. It's not a compiler flag.