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A simple address book example

Let's start with a very simple C++ application: an address book. This contrived simple piece of code contains everything we need to take you through the basics of using OI. The code itself can be found in the examples/web/AddrBook directory in the OI GitHub repo.

First, build the test application:

$ ~/object-introspection/examples/web/AddrBook: make CC=clang++-12
clang++-12 -o addrbook AddrBook.cpp -std=c++20 -g -O3

(No need to override the 'CC' make variable if you have clang++ in your path).

You can see the DWARF data is present in the generated executable:

$ ~/object-introspection/examples/web/AddrBook# size -At addrbook | grep "\.debug"
.debug_info 71316 0
.debug_abbrev 2446 0
.debug_line 8971 0
.debug_str 44990 0
.debug_loc 27968 0
.debug_ranges 10240 0

Each address book is composed of a single AddressBook object which contains zero or more Contact objects. Here's how the data and interface definitions look for the two objects:

class Contact {
Contact(std::string& f, std::string& l, std::string& n);
std::string firstName, lastName;
std::string number;

class AddressBook {
void AddContact(std::string& f, std::string& l, std::string& n);
void DumpContacts(void);
int rev;
std::string Owner;
std::vector<Contact> Entries;

OI can introspect objects at specific points in an application:

  • Function arguments upon entry to a function.
  • Function arguments upon return to a function.
  • The return value from a function.
  • This `this` pointer at entry or return from an object method.
  • Global objects.

Let's get started by introspecting an object using its this pointer.