Thread: Undefined Reference Error

I am getting an Undefined reference to <function>, here is my code:

Code:

#include <stdio.h>
#include "qsolver.h"


int main() {
	double a, b, c, x1, x2;
	int qret;

	while(1) {
		printf("Enter variables for quadratic equation (type: \n");
		scanf("%lf %lf %lf", &a, &b, &c);

		if((qret = qsolver(a, b, c, &x1, &x2)) != 0) {
			printf("Error Value:  %d\n", qret);
		}
	}
	return 0;
}

******************************************************************************

#include <stdio.h>
#include <math.h>
#include "qsolver.h"

int qsolver(double a, double b, double c, double* x1, double* x2) {

	//Is the user giving an input which would divide by zero?
	if(a == 0) {
		printf("Input Not A Quadratic; Cannot Have Value Of '0' For A\n");
		return 1;
	}

	//Is the user giving and input which would try to compute a square root of a negative number.
	else if( (4*a*c) > pow(b,2) ) {
		printf("There Are No Real Solutions; B^2 Is Less Than (4*A*C)\n");
		return 2;
	}

	//The user input is valid, solve accordingly
	else {
		*x1 = (-b + sqrt(pow(b,2) - (4*a*c)))/(2*a);
		*x2 = (-b - sqrt(pow(b,2) - (4*a*c)))/(2*a);
		
		return 0;
	}
}

*****************************************************************************************

#ifndef QSOLVER_H
#define QSOLVER_H

int qsolver(double, double, double, double *, double *);

#endif

You'll have to compile all your .c files and link them together. (Most people don't actually run the linker separately; usually your compiler will do it for you, but you have to compile your .c files together.)

I have a Makefile I am using to link the files together but I am still getting the error. If you would like I can post that also

Well, that wouldn't hurt.

The function is qsolver; here is the code to the makefile also which I believe links the math library:

Code:

CC = gcc
CFLAGS= -Wall -pedantic

q:  q.o q.solver.o
	${CC} -o q q.o qsolver.o -lm
q.o:  q.s
	${CC} -c q.s
qsolver.o:  qsolver.s
	${CC} -c qsolver.s
q.s:  q.c qsolver.h
	${CC} ${CFLAGS} -s q.c
qsolver.s:  qsolver.c qsolver.h
	${CC} ${CFLAGS} -s qsolver.c
clean:
	rm -f *.o *.s q core

Code:

q:  q.o q.solver.o

Shouldn't q.solver.o be qsolver.o?

Brewbuck what are you talking about????? That was my actual makefile. No need to get offensive here. I was thanking you for fixing my problem.............

Alrighty, thank you very much for your help. Otherwise I would have been sitting thinking for a while trying to figure it out haha.