title: Arduino C: undefined reference to `readArms()'
body: <p>While compiling some Arduino C file I get an error "undefined reference to `readArms()'"</p>
  
  <p>The code can be found on <a href="http://pastebin.com/NQD5mLGE" rel="noreferrer">paste bin</a>.</p>
  
  <p>But basically what happens is:</p>
  
  <p>In the INO file I use:</p>
  
  <pre><code>readArms();
  </code></pre>
  
  <p>Which is declared in "armfunctions.h" and "armfunctions.c"</p>
  
  <p>The .h file contains</p>
  
  <pre><code>void readArms(void);
  </code></pre>
  
  <p>And the .c file :</p>
  
  <pre><code>void readArms(void){
      float motor1 = 0.0;
      int motor = 0;
      motor = analogRead(READMOTOR1);
      motor1 = (float)motor;
      motor1 = (motor1 - 87.0) * (400.0/(1007.0-87.0));
      delay(1000);
  }
  </code></pre>