log function causing an error

[jbsloan]

I am currently working on a program that includes a special exponential function that calls the log function from with in it. (*the code is below). I am getting the following error:

gcc -c gas.c
gcc gas.o list.o queue.o -o gas.exe
Undefined first referenced
symbol in file
log gas.o

which seems to mean that it is not understanding the log function, however I am certain that the math.h library is inclued. Can there be another reason for this error?

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include "bool.h"
#include "gas.h"

double exponential(double mean)
{
double rnx;
rnx = drand48();
return (mean * -1.0 * log(rnx));
}

[Prelude]

You included math.h, but forgot to link with the math library.

% gcc gas.o list.o queue.o -o gas.exe -lm

[ZAK]

Also, you have a bug in your code if your variable rnx = 0 then the log function will tend towards infinity, theres an asymptote at log(0), you can think of it being undefined you may want to make sure you don't allow rnx to be 0. This is ofcourse assuming that your random number generator is Gaussian (ie. generating a normal distribution of values between 0.0 and 1.0)