/*
 * deep_thought.c: Obtain the answer to life, the universe, 
 * and everything, and act startled when you actually hear it.
 */
#include <stdio.h>
int main( )
{
  int the_answer;
  the_answer = get_answer( );
  printf("The answer is... %d\n", the_answer);

  fprintf(stderr, "%d??!!\n", the_answer);
  return 0;
}

# Makefile: Create and test a shared library.
#
# Usage: make test
#
CC = cc 
LD = cc
CFLAGS = -O -fno-common

all: deep_thought

# Create the shared library.
#
answer.o: answer.c
        $(CC) $(CFLAGS) -c answer.c

libanswer.dylib: answer.o
        $(LD) -dynamiclib -install_name libanswer.dylib \
        -o libanswer.dylib answer.o

# Test the shared library with the deep_thought program.
#
deep_thought.o: deep_thought.c
        $(CC) $(CFLAGS) -c deep_thought.c

deep_thought: deep_thought.o libanswer.dylib
        $(LD) -o deep_thought deep_thought.o -L. -lanswer

test: all
        ./deep_thought

clean:
        rm -f *.o core deep_thought libanswer.dylib

/*
 * deep_thought_dyld.c: Obtain the answer to life, the universe,
 * and everything, and act startled when you actually hear it.
 */
#include <stdio.h>
#import <mach-o/dyld.h>

int main( )
{
  int the_answer;
  int rc;                // Success or failure result value
  NSObjectFileImage img; // Represents the bundle's object file
  NSModule handle;       // Handle to the loaded bundle
  NSSymbol sym;          // Represents a symbol in the bundle

  int (*get_answer) (void);  // Function pointer for get_answer

  /* Get an object file for the bundle. */
  rc = NSCreateObjectFileImageFromFile("libanswer.bundle", &img);
  if (rc != NSObjectFileImageSuccess) {
    fprintf(stderr, "Could not load libanswer.bundle.\n");
    exit(-1);
  }

  /* Get a handle for the bundle. */
  handle = NSLinkModule(img, "libanswer.bundle", FALSE);

  /* Look up the get_answer function. */
  sym = NSLookupSymbolInModule(handle, "_get_answer");
  if (sym == NULL)
  {
    fprintf(stderr, "Could not find symbol: _get_answer.\n");
    exit(-2);
  }

  /* Get the address of the function. */
  get_answer = NSAddressOfSymbol(sym);

  /* Invoke the function and display the answer. */
  the_answer = get_answer( );
  printf("The answer is... %d\n", the_answer);

  fprintf(stderr, "%d??!!\n", the_answer);
  return 0;
}