### main.c ###

#include <stdio.h>
#include <dlfcn.h>


/* Call bridge function */
void call_bridge(const char* filename)
{
    // Open the library
    const char* libname = "bridge.so";
    printf("Opening library : %s\n", libname);
    void* handle;
    handle = dlopen(libname, RTLD_LAZY);
    handle ? printf("OK\n") : printf("KO\n\t%s\n", dlerror());
    if (handle)
    {
        // Load the symbol
        const char* symname = "ruby";
        printf("Load symbol : %s\n", symname);
        typedef void (*symbol_t)();
        symbol_t my_dlfunc = (symbol_t) dlsym(handle, symname);
        const char *dlsym_error = dlerror();
        !dlsym_error ? printf("OK\n") : printf("KO\n\t%s\n", dlsym_error);
        // Execute the function
        if (!dlsym_error) my_dlfunc(filename);
        // Close the library if opened
        printf("Closing library\n");
        int status = dlclose(handle);
        (status==0) ? printf("OK\n") : printf("KO\n\t%s\n", dlerror());
    }
}

/* Main function */
int main(int argc, char **argv)
{
    const int nb_run = 3;
    for (int i=0; i<nb_run; i++) call_bridge(argv[1]);
    return 0;
}


### bridge.c ###

#include "ruby.h"

/* Ruby interpreter routine */
void ruby(const char* filename)
{
    // INITIALIZATION
    RUBY_INIT_STACK
    ruby_init();
    ruby_init_loadpath();
    ruby_script(filename);
    // EXECUTION
    //VALUE content = rb_funcall(rb_cFile, rb_intern("read"), 1, rb_str_new2(filename));
    VALUE content = rb_str_new2("puts RUBY_VERSION; require 'fileutils'");
    //VALUE content = rb_str_new2("puts RUBY_VERSION");
    rb_define_const(rb_cObject, "RUBY_SCRIPT", content);
    printf("Before rb_eval_string()\n");
    rb_eval_string("eval(RUBY_SCRIPT, nil, $0, 1)");
    printf("After rb_eval_string()\n");
    // FINALIZATION ???
    //ruby_finalize();
    ruby_cleanup(0);
}

### Compilation script ###

#!/bin/csh -f

# Settings
set RUBY_H_FILE = <user defined>
set RUBY_SOLIB = <user defined>
setenv LD_LIBRARY_PATH ".:$RUBY_SOLIB:$LD_LIBRARY_PATH"
# Compilation
gcc -g -fPIC -Wall -std=c99 -I$RUBY_H_FILE -c bridge.c
ld -shared --export-dynamic -L$RUBY_SOLIB -lruby bridge.o -o bridge.so
gcc -g -Wall -std=c99 -ldl main.c -o main
# Simulation
./main