bob.example.cmake 1.0.1

Example project using Bob C++ interface

Example project using Bob’s C++ interface

This example project shows a way to incorporate Bob’s C++ libraries into a C++ project. For this, is uses the CMake interface, and a home-developed FindBob.cmake file. It relies on the python interface to download and install Bob. More information about the Bob installation can be found on its webpage.

This package is licensed under a BSD-3 license with a copyright of the Regents of the University of Colorado on behalf of the University of Colorado Colorado Springs. Please see LICENSE file for details.

Building this example

As the example requires some Bob packages to be installed, we first run one of the ways to install Bob, i.e., using buildout. For that, simply go to the main directory of this package and call:

$ python bootstrap-buildout.py
$ ./bin/buildout

This will checkout some of the packages to the src directory, and download some into the eggs directory. If you have Bob installed globally, it will use the globally installed packages instead of downloading new eggs. If you have Bob installed in a non-default directory, for example in an virtual environment, you can use that python version to bootstrap.

Inside of this package I have prepared a small CMake project that includes some of the Bob packages. It uses the FindBob.cmake to locate Bob’s include directories and libraries. To enable that, you can use the find_package(Bob COMPONENTS <package(s)> REQUIRED) command to find the list of bob package(s). Later, you can use three CMake variables Bob_INCLUDE_DIRS, Bob_LIBRARY_DIRS, Bob_LIBRARIES and Bob_DEFINITIONS and add it to your project:

cmake_minimum_required(VERSION 2.8)
project(test)

# Set the module path so that "FindBob.cmake" is found
set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR})

# Find all Bob packages recursively
find_package(Bob COMPONENTS bob.io.image REQUIRED)

# Add Bob's include directories
include_directories(${Bob_INCLUDE_DIRS})
# Add Bob's library directories
link_directories(${Bob_LIBRARY_DIRS})
# Add Bob's libraries
link_libraries(${Bob_LIBRARIES} boost_system)
# Add Bob's definitions
add_definitions(${Bob_DEFINITIONS})

# create an "my_test" executable from file "test.cpp"
add_executable(my_test test.cpp)

For some reason (that I do not understand) we also need to add the boost_system library, although it should theoretically be linked to the Bob libraries already.

So, now we can go ahead and compile our package using CMake:

$ mkdir build
$ cd build
$ cmake ..
$ make

and we should get an executable my_test inside the build directory. Note that you can pass a variable to CMake to use a custom Bob installation:

$ cmake .. -DBOB_PREFIX_PATH=/path/to/your/bob/installation

or set the BOB_PREFIX_PATH environment variable accordingly. If you have a local directory containing (some of) the Bob packages inside src or eggs sub-directories, you can set the BOB_SOURCE_DIR variable, which defaults to the directory where the CMakeLists.txt is located:

$ cmake .. -DBOB_SOURCE_DIR=/path/to/your/local/bob/packages

The evaluation order of the directories is:

1. ${BOB_SOURCE_DIR}/src

2. ${BOB_SOURCE_DIR}/eggs

3. ${BOB_PREFIX_PATH}/lib/*/site-packages (where * typically is your python version)

4. the system path

To run the example, go back to the package base directory (otherwise it will not find the example image) and call:

$ ./build/my_test

This should create an HDF5 file called test.hdf5 inside the current directory.