[redhead]

A small program to read lines from a file:
(Note program has not been testet, not even compiled)

/* 
 * needed includes in order to use:
 * fopen(), fgets(), fclose() and printf()
 */
#include <stdio.h>

/*
 * In order to have a precise line length we're going for everytime
 * we define the LINE_SIZE
 */
#define LINE_SIZE 256

/*
 * Definition of function beeing used by main(),
 * also known as the prototype.
 */
int read_file(char* file_name);

/*
 * main() is a function which is invoked with every argument given
 * in the program call.
 * argc: tells you how many arguments given (including program name)
 * argv: an array of char* with the arguments parsed to the program
 */
int main(int argc, char* argv[])
{
  int status = 0;
  if(argc != 2)
  {
    printf("Usage: %s <file_name>\n", 
            argv[0]);
    return -1;
  {
  if(0 != (status = read_file(argv[1]))
    printf("Reading of file [%s] failed with status: %d\n", 
            argv[1], status);
  return status;
}

/*
 * read_file() is the actual function to open/read and print
 * what has been read from the file.
 * Depending on where it might fail, it will return an error code
 * to which the caller can act apropriate on.
 */
int read_file(char* file_name)
{
  FILE* file;
  char buffer[LINE_SIZE];
  int i = 0;
  file = fopen(file_name);
  if(!file)
    return -1;
  while(!feof(file))
  {
      if(!fgets(buffer, LINE_SIZE, file))
      {
         fclose(file);
         return -2;
      }
      printf("Line (%d) in file [%s]: %s\n",
              ++i, file_name, buffer);
  }
  fclose(file);
  return 0;
}

Another thing whats the format for writing and declaring a function prototype the returns more than one object?

In short you can't.
C dosn't allow you to return different types of objects, the function prototype can be declared to return a specific struct, and this can consist of pointers to different objects/structs/types, where the function can either set these to NULL or point to the resulting object.

An ugly way of achieving it, is to have a function which returns a void* and then later on typecast that to whatever you would use, but that's just insane, since a void* wont tell you what type it intentionaly was.