Different behaviors when using the SIP library in interactive and normal mode

Question

I'm trying to follow the tutorial on this page (I've also added my own simple 'get' method). I'm getting different results whether I use the interactive or normal Python mode.

Normal mode

word_test.py

from word import Word

foo = Word("reverse me")
print foo.get()
print foo.reverse()

Shell

$ python word_test.py 
reverse me
em esrever

Everything works as expected! Yay!

Interactive mode

Shell

$ python
Python 2.7.6 (default, Mar 22 2014, 22:59:56) 
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from word import Word
>>> foo = Word("reverse me")
>>> print foo.get()

>>> print foo.reverse()

foo.get() and foo.reverse() both return an empty string! What gives?

My source files

word.sip

%Module word

class Word {

%TypeHeaderCode
#include <word.h>
%End

public:
    Word(const char *w);

    char *reverse() const;

    char *get() const;
};

word.cpp

#include <string.h>
#include <iostream>
#include <word.h>

using namespace std;

Word::Word(const char *w)
{
    the_word = w;
}

char* Word::reverse() const
{
    int len = strlen(the_word);
    char *str = new char[len+1];
    
    for (int i = len-1 ; i >= 0 ; i--) {
        str[len-1-i] = the_word[i];
    }

    str[len]='\0';
    return str;
}

char* Word::get() const
{
    return (char*) the_word;
}

word.h

class Word {
    const char *the_word;

public:
    Word(const char *w);

    char *reverse() const;

    char *get() const;
};

configure.py

import os
import sipconfig

# The name of the SIP build file generated by SIP and used by the build
# system.
build_file = "word.sbf"

# Get the SIP configuration information.
config = sipconfig.Configuration()

# Run SIP to generate the code.
os.system(" ".join([config.sip_bin, "-c", ".", "-b", build_file, "word.sip"]))

# Create the Makefile.
makefile = sipconfig.SIPModuleMakefile(config, build_file)

# Add the library we are wrapping.  The name doesn't include any platform
# specific prefixes or extensions (e.g. the "lib" prefix on UNIX, or the
# ".dll" extension on Windows).
makefile.extra_libs = ["word"]

# Generate the Makefile itself.
makefile.generate()

Shell script to compile and move the lib to /usr/lib

run.sh (needs root access)

#!/bin/bash
python configure.py
g++ -c -fPIC -I. word.cpp
ar -crs libword.a word.o
cp libword.a /usr/lib
make
make install