title: C Linking Error: undefined reference to 'main'
body: <p>I have read the other answers on this topic, and unfortunately they have not helped me. I am attempting to link several c programs together, and I am getting an error in response:</p>
  
  <pre><code>$ gcc -o runexp.o scd.o data_proc.o -lm -fopenmp
  /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/crt1.o: In function `_start':
  (.text+0x20): undefined reference to `main'
  collect2: ld returned 1 exit status
  make: * [runexp] Error 1
  </code></pre>
  
  <p>I have exactly one main function and it is in runexp. The form is </p>
  
  <pre><code>int main(void) {
      ...; 
      return 0;
  }
  </code></pre>
  
  <p>Any thoughts on why I might get this error? Thanks!</p>