Undefined function error reference in C
I have created a header file called dm.h that includes all the function prototypes. Then I created a source file called dm.c that includes the source code for all the functions declared in indm.h. After that I started coding in main.c, but when I ran it I got an error: undefined reference to "(function name)". I am getting this error for all my functions.
Below you can find the source code for all of my three files.
ofdm.h
#ifndef OFDM_H_INCLUDED
#define OFDM_H_INCLUDED
typedef struct {
double real, img;
} Complex;
char** split(char *s, const char *delim);
void parseComplex(Complex *c, char *line);
void rbits(short* buf, int nbits);
void printbinary(short* buf, int len);
void printcomplex(Complex* buf, int len);
long bin2dec(short *bin, int len);
void dec2bin(long dec, short *bin, int len);
void binaryadd(short *bin1, short *bin2, short *erg, int len);
void leftshift(short *bin,short *erg,int shifts, int len);
void binarymult(short *bin1, short *bin2, short *erg, int len);
void binarypower(short *bin,short *erg,int power, int len);
void scrambler(short *seed, short *input, short *output, int len, int seedlen);
void encoder(short *input, short *output, int inputlen);
void interleaver(short *input, short *output, int N_CBPS,int N_BPSC);
void deinterleaver(short *input, short *output, int N_CBPS,int N_BPSC);
void fixed_point(short* input, int nbits);
void fixed_point_complex(Complex* input, int nbits);
void defixed_point(short* input, int nbits);
void BPSKmapping(short* input, short* output, int nbits);
void BPSKdemapping(short* input, short* output, int nbits);
void QPSKmapping(short* input, Complex* output, int nbits);
void QPSKdemapping(Complex* input, short* output, int nbits);
void IFFT_BPSK(short* input, Complex* output, Complex* twidder);
void IFFT_QPSK(Complex* input, Complex* output, Complex* twidder);
double uniform(double a, double b);
double gauss(double mean, int SNRdb);
void ChannelModel(Complex R[], Complex S[], int SNRdb);
#endif
ofdm.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "ofdm.h"
char** split(char* string, const char* delim)
{
char* p;
int i = 0;
char** array = malloc(strlen(string) * sizeof(char*));
p = strtok(string, delim);
while(p != NULL)
{
array[i] = malloc(sizeof(char));
array[i++] = p;
p = strtok(NULL, delim);
}
return array;
}
void parseComplex(Complex *cmplx, char *number)
{
char *copy = number;
if(strchr(copy, ' ') != NULL)
{
char **result = split(copy, " ");
cmplx->real = atof(*result++);
char *sign = *result++;
cmplx->img = atof(*result++);
if(sign[0] == '-')
cmplx->img = -(cmplx->img);
}
else if(strchr(copy, 'j') != NULL)
{
cmplx->real = 0;
cmplx->img = atof(copy);
}
else
{
cmplx->real = atof(copy);
cmplx->img = 0;
}
}
void rbits(short* buf, int nbits)
{
int i;
for(i = 0; i < nbits; i++)
buf[i] = (rand() % 2);
}
void printbinary(short* buf, int len)
{
int i;
for(i = 0; i < len; i++)
{
printf("%d\t", buf[i]);
}
printf("\n\n\n");
}
void printcomplex(Complex* buf, int len)
{
int i;
for(i = 0; i < len; i++)
{
printf("%.0lf %.0lf\t", buf[i].real, buf[i].img);
}
printf("\n\n");
}
long bin2dec(short *bin, int len)
{
long dec = 0;
int i;
for(i = 0;i < len;i++)
{
dec += bin[i]*pow(2.0,(double) (len - i -1));
}
return dec;
}
void dec2bin(long dec, short *bin, int len)
{
long temp = dec;
int i;
for(i = 0;i<len;i++)
{
bin[len - 1 - i] = temp % 2;
temp = temp/2;
}
}
void binaryadd(short *bin1, short *bin2, short *erg, int len)
{
int i;
short carry = 0;
short oldcarry = 0;
for(i = len - 1; i >= 0; i--)
{
if((bin1[i] + bin2[i] + oldcarry) > 1)
{
carry = 1;
}
else
{
carry = 0;
}
erg[i] = (bin1[i] + bin2[i] + oldcarry) % 2;
oldcarry = carry;
}
}
void leftshift(short *bin,short *erg,int shifts, int len)
{
int i;
for(i = 0;i < len - shifts;i++)
{
erg[i] = bin[i + shifts];
}
for(i = len - shifts;i < len;i++)
{
erg[i] = 0;
}
}
void binarymult(short *bin1, short *bin2, short *erg, int len)
{
int i;
short temp[len - 1];
for(i = 0;i < len;i++)
{
erg[i] = 0;
}
for(i = 0;i < len;i++)
{
if(bin2[i] == 1)
{
leftshift(bin1,temp,len - 1 - i,len);
binaryadd(temp,erg,erg,len);
}
}
}
void binarypower(short *bin,short *erg,int power, int len)
{
int i;
short temp[len - 1];
for(i = 0;i < len;i++)
{
temp[i] = 0;
}
temp[len - 1] = 1;
if(power > 1)
binarypower(bin,temp,power - 1,len);
binarymult(temp,bin,erg,len);
}
void scrambler(short *seed, short *input, short *output, int len, int seedlen)
{
int i;
short carry;
short sequence[len - 1];
for(i = 0; i < len; i++)
{
sequence[i] = (seed[0] + seed[3]) % 2;
carry = (seed[0] + seed[3]) % 2;
leftshift(seed,seed,1,seedlen);
seed[seedlen - 1] = carry;
output[i] = (sequence[i] + input[i]) % 2;
}
}
void encoder(short *input, short *output, int inputlen)
{
int i;
short SR[7] = {0,0,0,0,0,0,0};
short A;
short B;
for(i = 0; i < inputlen;i++)
{
leftshift(SR,SR,1,7);
SR[6] = input[i];
A = (SR[6] + SR[4] + SR[3] + SR[1] + SR[0]) % 2;
B = (SR[6] + SR[5] + SR[4] + SR[3] + SR[0]) % 2;
output[2*i] = A;
output[2*i + 1] = B;
}
}
/*
void decoder(short *input, short *output, int inputlen)
{
int i;
short SR[7] = {0}
short A;
short B;
short C1;
short C2;
for(i = 0; i < intputlen; i++)
{
leftshift(SR, SR, 1, 7)
SR[6] = input[i];
C1 = (SR[6] + SR[4] + SR[3] + SR[1] + SR[0]) / 2;
C2 = (SR[6] + SR[5] + SR[4] + SR[3] + SR[0]) / 2;
A = (SR[6] + SR[4] + SR[3] + SR[1] + SR[0]) - (2 * C1);
B = (SR[6] + SR[5] + SR[4] + SR[3] + SR[0]) - (2 * C2);
output[2*i] = A; // output[i/2] = A;
output[2*i + 1] = B; // output[i/2 + 1] = B;
}
}
*/
void interleaver(short *input, short *output, int N_CBPS,int N_BPSC)
{
int i;
int t;
int k;
int s;
short first_permutuation[N_CBPS - 1];
for (k = 0; k < N_CBPS; k++)
{
i = (N_CBPS/16)*(k % 16) + (k/16);
first_permutuation[i] = input[k];
}
s = fmax(N_BPSC/2,1);
for(i = 0; i < N_CBPS;i++)
{
t = s*(i/s) + (i + N_CBPS - ((16*i)/N_CBPS)) % s;
output[t] = first_permutuation[i];
}
}
void fixed_point(short* input, int nbits)
{
int i;
for(i = 0; i < nbits; i++)
{
if(input[i] < 0)
input[i] *= 32768;
else input[i] *= 32767;
}
}
void fixed_point_complex(Complex* input, int nbits)
{
int i;
for(i = 0; i < nbits; i++)
{
if(input[i].real == -1 || input[i].img == -1)
input[i] *= 32768;
else input[i] *= 32767;
}
}
void defixed_point(short* input, int nbits)
{
int i;
for(i = 0; i < nbits; i++)
{
if(input[i] < 0)
input[i] /= 32768;
else input[i] /= 32767;
}
}
void IFFT_BPSK(short* input, Complex* output, Complex* twidder)
{
int i, k;
for(i = 0; i < 64; i++)
{
for(k = 0; k < 64; k++)
{
output[i].real += (twidder[i][k].real * input[i]) / 64;
output[i].img += (twidder[i][k].img * input[i]) / 64;
}
}
}
void IFFT_QPSK(Complex* input, Complex* output, Complex* twidder)
{
int i, k;
for(i = 0; i < 64; i++)
{
for(k = 0; k < 64; k++)
{
output[i].real += (twidder[i][k].real * input[i].real) / 64;
output[i].img += (twidder[i][k].img * input[i].img) / 64;
}
}
}
void IFFT_QPSK2(Complex* input, Complex* output, Complex* twidder, int nbits)
{
int a, b, c, d, e, f, g, h, blocks;
int count1 = 7, count2 = 20, count3 = 28, count4 = 41;
int next = 0;
Complex ifft_qpsk_output[64];
blocks = nbits / 48;
for(a = 1; a <= blocks; a++)
{
// pilots
output[7].real = 32767;
output[21].real = 32767;
output[42].real = 32767;
output[56].real = -32768;
// some data
output[40].real = input[26 + (next * 48)].real;
output[40].img = input[26 + (next * 48)].img;
output[41].real = input[27 + (next * 48)].real;
output[41].img = input[27 + (next * 48)].img;
// zeroes
for(b = 28; b <= 39; b++)
output[b].real = 0;
// other data
for(c = 0; c <= 6; c++)
{
output[c].real = input[c + (next * 48)].real;
output[c].img = input[c + (next * 48)].img;
}
for(d = 8; d <= 20; d++)
{
output[d].real = input[count1++ + (next * 48)].real;
output[d].img = input[count1++ + (next * 48)].img;
}
for(e = 22; e <= 27; e++)
{
output[e].real = input[count2++ + (next * 48)].real;
output[e].img = input[count2++ + (next * 48)].img;
}
for(f = 43; f <= 55; f++)
{
output[f].real = input[count3++ + (next * 48)].real;
output[f].img = input[count3++ + (next * 48)].img;
}
for(h = 57; h <= 63; h++)
{
output[h].real = input[count4++ + (next * 48)].real;
output[h].img = input[count4++ + (next * 48)].img;
}
// IFFT function goes here
IFFT_QPSK(output, ifft_qpsk_output, twidder);
printcomplex(ifft_qpsk_output, 64);
next++;
}
}
void IFFT_BPSK2(short* input, short* output, Complex* twidder, int nbits)
{
int a, b, c, d, e, f, g, h, blocks;
int count1 = 7, count2 = 20, count3 = 28, count4 = 41;
int next = 0;
Complex ifft_bpsk_output[64];
blocks = nbits / 48;
for(a = 1; a <= blocks; a++)
{
// pilots
output[7] = 32767;
output[21] = 32767;
output[42] = 32767;
output[56] = -32768;
// some data
output[40] = input[26 + (next * 48)];
output[41] = input[27 + (next * 48)];
// zeroes
for(b = 28; b <= 39; b++)
output[b] = 0;
// other data
for(c = 0; c <= 6; c++)
output[c] = input[c + (next * 48)];
for(d = 8; d <= 20; d++)
output[d] = input[count1++ + (next * 48)];
for(e = 22; e <= 27; e++)
output[e] = input[count2++ + (next * 48)];
for(f = 43; f <= 55; f++)
output[f] = input[count3++ + (next * 48)];
for(h = 57; h <= 63; h++)
output[h] = input[count4++ + (next * 48)];
// IFFT function goes here
IFFT_BPSK(output, ifft_bpsk_output, twidder);
printcomplex(ifft_bpsk_output, 64);
next++;
}
}
void BPSKmapping(short* input, short* output, int nbits)
{
int i;
for(i = 0; i < nbits; i++)
{
if(input[i] == 0)
output[i] = -1;
else output[i] = 1;
}
}
void BPSKdemapping(short* input, short* output, int nbits)
{
int i;
for(i = 0; i < nbits; i++)
{
if(input[i] == -1)
output[i] == 0;
else output[i] == 1;
}
}
void QPSKmapping(short* input, Complex* output, int nbits)
{
int i;
for(i = 0; i < nbits; i += 2)
{
if(input[i] == 0 && input[i+1] == 0)
{
output[i].real = -1;
output[i+1].img = -1;
}
else if(input[i] == 0 && input[i+1] == 1)
{
output[i].real = -1;
output[i+1].img = 1;
}
else if(input[i] == 1 && input[i+1] == 0)
{
output[i].real = 1;
output[i+1].img = -1;
}
else
{
output[i].real = 1;
output[i+1].img = 1;
}
}
}
void QPSKdemapping(Complex* input, short* output, int nbits)
{
int i;
for(i = 0; i < nbits; i += 2)
{
if(input[i].real == -1 && input[i+1].img == -1)
{
output[i] = 0;
output[i+1] = 0;
}
else if(input[i].real == -1 && input[i+1].img == 1)
{
output[i] = 0;
output[i+1] = 1;
}
else if(input[i].real == 1 && input[i+1].img == -1)
{
output[i] = 1;
output[i+1] = 0;
}
else
{
output[i] = 1;
output[i+1] = 1;
}
}
}
//Channel Begin
double uniform(double a, double b)
{
double c;
double d;
static int firstcall = 1;
c = b - a;
if(firstcall == 1)
{
srand((unsigned int)time(NULL));
firstcall = 0;
}
d = a + (double)rand() / RAND_MAX * c;
return d;
}
double gauss(double mean, int SNRdb)
{
double dGaussNum;
double x = 0;
int i;
double sigma;
sigma = 1 / pow(10, (double)SNRdb / 10);
for(i = 0;i < 12; i ++)
{
x = x + uniform(0,1);
}
x = x - 6;
dGaussNum = mean + sqrt(sigma) * x;
return dGaussNum;
}
void ChannelModel(Complex R[], Complex S[], int SNRdb)
{
int i;
for (i=0;i<N+L;i++)
{
R[i].real = S[i].real + gauss(0, SNRdb);
R[i].img = S[i].img + gauss(0, SNRdb);
}
}
//Channel End
void deinterleaver(short *input, short *output, int N_CBPS,int N_BPSC)
{
int i;
int t;
int k;
int s;
short first_permutuation[N_CBPS - 1];
s = fmax(N_BPSC/2,1);
for (t = 0; t < N_CBPS; t++)
{
i = s*(t/s) + (t + ((16*t)/N_CBPS)) % s;
first_permutuation[i] = input[t];
}
for(i = 0; i < N_CBPS;i++)
{
k = 16*i - (N_CBPS - 1)*((16*i)/N_CBPS);
output[k] = first_permutuation[i];
}
}
main.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "ofdm.h"
int main(int argc, char *argv[])
{
short seed[8];
int bits, i, j, k;
char mode[5], line[1024];
/* Complex twidder[64][64];
FILE *file = fopen("twidder_factor.txt", "r");
i = 0;
while(fgets(line, sizeof(line), file ) != NULL)
{
k = j = 0;
char **result = split(line, "\t");
while(result[k] != NULL)
{
parseComplex(&twidder[i][j], result[k++]);
j++;
}
i++;
}
*/
printf("How many bits do you want to transmit?: ");
scanf("%d", &bits);
short* start_input;
short* scrambler_output;
short* encoder_output;
short* interleaver_output;
short* bpsk_mapper_output;
short* ifft_bpsk_input[64];
Complex* qpsk_mapper_output;
Complex ifft_qpsk_input[64];
start_input = malloc(sizeof(short) * bits);
scrambler_output = malloc(sizeof(short) * bits);
encoder_output = malloc(sizeof(short) * (bits * 2));
interleaver_output = malloc(sizeof(short) * (bits * 2));
bpsk_mapper_output = malloc(sizeof(short) * (bits * 2));
qpsk_mapper_output = malloc(sizeof(Complex) * (bits * 2));
if(qpsk_mapper_output == NULL)
{
fprintf(stderr, "Couldn't allocate that much memory!\n");
return 1;
}
srand(time(NULL));
rbits(seed, 8);
rbits(start_input, bits);
printf("Which modulation type to you want to use? (type BPSK or QPSK): ");
scanf("%s", mode);
if((strcmp(mode, "BPSK") == 0) || (strcmp(mode, "bpsk") == 0))
{
printf("\nSelected modulation type: BPSK\n\n\n");
printf("SCRAMBLER OUTPUT:\n\n");
scrambler(seed, start_input, scrambler_output, bits, 8);
printbinary(scrambler_output, bits);
printf("ENCODER OUTPUT:\n\n");
encoder(scrambler_output, encoder_output, bits);
printbinary(encoder_output, bits*2);
printf("INTERLEAVER OUTPUT:\n\n");
interleaver(encoder_output, interleaver_output, bits, 1);
printbinary(interleaver_output, bits*2);
printf("MAPPER OUTPUT:\n\n");
BPSKmapping(interleaver_output, bpsk_mapper_output, bits*2);
printbinary(bpsk_mapper_output, bits*2);
printf("FIXED-POINT OUTPUT:\n\n");
fixed_point(bpsk_mapper_output, bits*2);
printbinary(bpsk_mapper_output, bits*2);
/*
printf("IFFT OUTPUT:\n\n");
IFFT_BPSK(bpsk_mapper_output, ifft_bpsk_input, twidder, bits*2)
defixed_point(bpsk_mapper_output, bits*2);
printbinary(bpsk_mapper_output, bits*2);
*/ }
else if((strcmp(mode, "QPSK") == 0) || (strcmp(mode, "qpsk") == 0))
{
printf("\nSelected modulation type: QPSK\n\n\n");
printf("SCRAMBLER OUTPUT:\n\n");
scrambler(seed, start_input, scrambler_output, bits, 8);
printbinary(scrambler_output, bits);
printf("ENCODER OUTPUT:\n\n");
encoder(scrambler_output, encoder_output, bits);
printbinary(encoder_output, bits*2);
printf("INTERLEAVER OUTPUT:\n\n");
interleaver(encoder_output, interleaver_output, bits, 2);
printbinary(interleaver_output, bits*2);
printf("MAPPER OUTPUT:\n\n");
QPSKmapping(interleaver_output, qpsk_mapper_output, bits*2);
printcomplex(qpsk_mapper_output, bits*2);
/*
printf("FIXED-POINT OUTPUT:\n\n");
fixed_point_complex(qpsk_mapper_output, bits*2);
printcomplex(qpsk_mapper_output, bits*2);
printf("IFFT OUTPUT:\n\n");
IFFT_QPSK(qpsk_mapper_output, ifft_qpsk_input, twidder, bits*2)
defixed_point(qpsk_mapper_output, bits*2);
printbinary(qpsk_mapper_output, bits*2);
*/ }
else
{
printf("That an invalid modulation type!\n");
free(start_input);
free(scrambler_output);
free(encoder_output);
free(interleaver_output);
free(bpsk_mapper_output);
free(qpsk_mapper_output);
return 0;
}
free(start_input);
free(scrambler_output);
free(encoder_output);
free(interleaver_output);
free(bpsk_mapper_output);
free(qpsk_mapper_output);
system("PAUSE");
return 0;
}
If you could help me solve this problem, I would be glad. I think there is some kind of linking issue between my library and the main source file.
Thanks in advance.
Since you are getting this error for all your functions, it cannot be a typo. It is best to assume that you are not linking the two files.
If you are using gcc it is done like this:
gcc -o main.o -c main.c
gcc -o ofdm.o -c ofdm.c
gcc -o program main.o ofdm.o
Note, which -c
means it should compile, but not try to create an executable. This means that the connection is not being made.
Once both files are compiled, you link them together.
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When you learn new things, it helps you learn one new thing at a time. Put your source code in source control, then simplify it to get a clean compiler.
main.c
#include "ofdm.h"
int main(int argc, char *argv[])
{
return 0;
}
ofdm.c
#include "ofdm.h"
void leftshift(short *bin,short *erg,int shifts, int len)
{
int i;
for(i = 0;i < len - shifts;i++)
{
erg[i] = bin[i + shifts];
}
for(i = len - shifts;i < len;i++)
{
erg[i] = 0;
}
}
ofdm.h
#ifndef OFDM_H_INCLUDED
#define OFDM_H_INCLUDED
void leftshift(short *bin,short *erg,int shifts, int len);
#endif
Then, to compile with gcc.,.
$ gcc -Wall -c ofdm.c $ gcc -Wall -c main.c $ gcc -Wall *.o
This should give you a program that does nothing, successfully. You can now start building it again from your version controlled source.
- Add one function at a time.
- Edit it to get a clean compiler.
- Edit this to pass sensible tests.
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