text: #ifndef _UTIL_H
  #define _UTIL_H
  
  /**********************************************
   * init
     - port is the number of the port you want the server to be
       started on
     - initializes the connection acception/handling system
     - YOU MUST CALL THIS EXACTLY ONCE (not once per thread,
       but exactly one time, in the main thread of your program)
       BEFORE USING ANY OF THE FUNCTIONS BELOW
     - if init encounters any errors, it will call exit().
  ************************************************/
  void init(int port);
  
  /**********************************************
   * accept_connection - takes no parameters
     - returns a file descriptor for further request processing.
       DO NOT use the file descriptor on your own -- use
       get_request() instead.
     - if the return value is negative, the request should be ignored.
  ***********************************************/
  int accept_connection(void);
  
  /**********************************************
   * get_request
     - parameters:
        - fd is the file descriptor obtained by accept_connection()
          from where you wish to get a request
        - filename is the location of a character buffer in which
          this function should store the requested filename. (Buffer
          should be of size 1024 bytes.)
     - returns 0 on success, nonzero on failure. You must account
       for failures because some connections might send faulty
       requests. This is a recoverable error - you must not exit
       inside the thread that called get_request. After an error, you
       must NOT use a return_request or return_error function for that
       specific 'connection'.
  ************************************************/
  int get_request(int fd, char *filename);
  
  /**********************************************
   * return_result
     - returns the contents of a file to the requesting client and cleans
       up the connection to the client
     - parameters:
        - fd is the file descriptor obtained by accept_connection()
          to where you wish to return the result of a request
        - content_type is a pointer to a string that indicates the
          type of content being returned. possible types include
          "text/html", "text/plain", "image/gif", "image/jpeg" cor-
          responding to .html, .txt, .gif, .jpg files.
        - buf is a pointer to a memory location where the requested
          file has been read into memory (the heap). return_result
          will use this memory location to return the result to the
          user. (remember to use -D_REENTRANT for CFLAGS.) you may
          safely deallocate the memory after the call to
          return_result (if it will not be cached).
        - numbytes is the number of bytes the file takes up in buf
     - returns 0 on success, nonzero on failure.
  ************************************************/
  int return_result(int fd, char *content_type, char *buf, int numbytes);
  
  /**********************************************
   * return_error
     - returns an error message in response to a bad request and cleans
       up the connection to the client
     - parameters:
        - fd is the file descriptor obtained by accept_connection()
          to where you wish to return the error
        - buf is a pointer to the location of the error text
     - returns 0 on success, nonzero on failure.
  ************************************************/
  int return_error(int fd, char *buf);
  
  #endif /* _UTIL_H */
  