title: warning: passing argument ’from incompatible pointer type [enabled by default]'
body: <p>I've been looking around on the other threads somehow related to this, but somehow I just don't get it...</p>
  
  <p>I want to do some FFT on a set of values I have evaluated and wrote this program to first read the values and save them to an array of size <code>n</code>.</p>
  
  <pre><code>int main () {
      // some variables and also a bit of code to read the 'messwerte.txt'
  
  printf("Geben sie an wieviele Messwerte ausgelesen werden sollen: ");
  scanf("%d", &amp;n);
  double werte[n]; //Array der "fertigen" Messwerte
  in = fopen ("messwerte.txt","r");
  double nul[n]; //Array von nullen
  
  int logN = 14;
  l=FFT(logN,&amp;werte,&amp;nul);
  }
  </code></pre>
  
  <p>In the same file I also do the FFT with the help of this program:</p>
  
  <pre><code>double FFT (int logN, double *real, double *im) //logN is base 2 log(N) {
  // blabla FFT calculation
  }
  </code></pre>
  
  <p>However, when I compile I always get this error:</p>
  
  <pre class="lang-none prettyprint-override"><code>gcc FFT.c -lm
  FFT.c: In function ‘main’:
  FFT.c:94:2: warning: passing argument 2 of ‘FFT’ from incompatible pointer type [enabled by default]
  FFT.c:4:8: note: expected ‘double *’ but argument is of type ‘double (*)[(unsigned int)(n)]’
  FFT.c:94:2: warning: passing argument 3 of ‘FFT’ from incompatible pointer type [enabled by default]
  FFT.c:4:8: note: expected ‘double *’ but argument is of type ‘double (*)[(unsigned int)(n)]’
  </code></pre>
  
  <p>Since this is my first time programming, I really don't know what is wrong with my code. Will I have to set more flags for the compiler or stuff like that (because I had to do this <code>-lm</code> stuff or it wouldn't compile and said something like pow not found or so)?</p>
  
  <p>Also I was made aware that there might be a difference when writing on a Windows or a Linux machine, and I am using Linux, Lubuntu 12.10 32-bit if it's a problem of the OS.</p>