Example of ECL in a C program.

ecldemo.c

/*
    Example of a C program embedding ECL with callbacks to C functions.
    Compiled via: gcc ecldemo.c -lecl
 */
#include <stdio.h>
#include <stdlib.h>
#include "ecl/ecl.h"

#define DEFUN(name,fun,args) \
    cl_def_c_function(c_string_to_object(name), \
                      (cl_objectfn_fixed)fun, \
                      args)

cl_object foo() {
    return ecl_make_integer(42);
}

cl_object bar(cl_object a, cl_object b) {
    int aval = fix(a);
    int bval = fix(b);
    return ecl_make_integer(aval + bval);
}

/*
    Assumes the string is a valid call.
*/
cl_object ecl_call(char *call) {
    return cl_safe_eval(c_string_to_object(call), Cnil, Cnil);
}

void init() {
    cl_boot(1, (char **)&"");

    atexit(cl_shutdown);

/* 
    Uncomment these lines to place your code into a separate package,
    They may then be called like (my-code:foo)
 */
//  ecl_call("(make-package :my-code)");
//  ecl_call("(in-package my-code)");

    DEFUN("foo", foo, 0);
    DEFUN("bar", bar, 2);

//  ecl_call("(export foo)");
//  ecl_call("(export bar)");
//  ecl_call("(in-package common-lisp-user)");
}

int main() {
    init();
    cl_object exit_obj = c_string_to_object(":EXIT");
    cl_object result = Cnil;

    while (cl_equal(exit_obj, result) == Cnil) {
        printf("\n> ");
        cl_object form = ecl_call("(read)");
        result = cl_safe_eval(form, Cnil, Cnil);
        cl_print(1, result);
    }
    putchar('\n');

    return 0;
}

Ported to VS11 on windows: https://github.com/fabriceleal/ecl-win-vs11-example