** Start of listing of h3.c **
/* I haven't verified this, but I think I built h3-c.cgi like this:
gcc h3.c cgis.o
mv h3-c.cgi ~/Trash/
mv a.out h3-c.cgi
*/

#include <stdio.h>
#include <time.h>
#include <stdlib.h>

/* Function prototype, see cgis.c: */
unsigned char *getval(unsigned char *);

int main(void) {
  unsigned char *rmstr;
  unsigned char *qus;
  unsigned char *stmp;

  printf("Content-type: text/plain;charset=us-ascii\n\n");

  printf("Working on new stuff...\n");
  rmstr = getenv("REQUEST_METHOD");
  if (rmstr == NULL) {
    printf("Request method returned NULL, why??\n");
    return -1;
  } else {
    printf("The request method is: [%s]\n", rmstr);
  }

  if (strcmp(rmstr,"POST") == 0) {
    printf("*** POST method not yet implemented\n");
    return -1;
  } else if (strcmp(rmstr,"GET") == 0) {
    qus = getenv("QUERY_STRING");
    printf("The query string is: [%s]\n", qus);
  } else {
    printf("*** Unknown request method, neither GET nor POST\n");
    return -1;
  }
  printf("* End of debug output.\n\n");

  printf("Starting to use Peter Burden's form-contents decoder:\n");
  stmp = getval((unsigned char *)("firstname"));
  printf("For key [firstname] the value is [%s].\n", stmp);
  stmp = getval((unsigned char *)("lastname"));
  printf("For key [lastname] the value is [%s].\n", stmp);
  stmp = getval((unsigned char *)("square root of 2"));
  printf("For key [square root of 2] the value is [%s].\n", stmp);
  return 0;
}
** End of listing of h3.c **

Here is the directory entry for that source file:
-rw-------  1 rem  user  1430 Feb 28  2007 h3.c
   ^ Note user execute permission *not* needed for source files.

That gets compiled to a.out, but then renamed to something.cgi
so that it will be usable by remote users via CGI:
-rwx------  1 rem  user  8402 Feb 28  2007 h3-c.cgi
   ^ Note user execute permission needed for all CGI programs.
(because compiled-C is native machine code running directly on machine)