hi everyone,I've very basic knowledge about programming.

As a part of program, i had to implement parallel processing in one program file, and that needs to be compiled using a make file. when i was compiling with -fopenmp it is showing the following error

undefined reference to GOMP_parallel_start
undefined reference to GOMP_parallel_end
undefined reference to omp_get_num_threads
undefined reference to omp_get_thread_num
undefined reference to GOMP_barrier

in make file target was written as

problemdef.o: problemdef.cpp
$(CXX) -fopenmp $(CXXFLAGS) $<


and the program was as follows

#include <vector>
#include <complex.h>
#include <iostream>
#include <time.h>
#include <math.h>
#include <cstdlib>
#include <stdio.h>
#include <string.h>
#include <omp.h>
#include <fstream>


#ifndef GLOBAL_H
#include "global.h"
#endif
#include "m_minrad.h"
#include "functs.h"

#define PAR // Comment out if not parallel version
using namespace std;

void test_problem(double* parameters)
{
int i;
#ifdef PAR
#pragma omp parallel for private(parameters,i)
#endif

for(i=0;i<3;i++)
{

obj[i]=function(parameters);
}
}

could anyone please find what's wrong with program or part of makefile,it would be of great help to me

It looks like the library containing the OpenMP functions is not being found by the compiler. Typically the library is named libgomp.so.<whatever>. You could check where the loader is looking for libraries by, say, ld --verbose | grep SEARCH_DIR