xref: /freebsd/contrib/libcbor/doc/source/getting_started.rst (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
1Getting started
2==========================
3
4Pre-built Linux packages are available in most mainstream distributions
5
6**Ubuntu, Debian, etc.**:
7
8.. code-block:: bash
9
10    apt-get install libcbor-dev
11
12**Fedora, openSUSE, etc.**:
13
14.. code-block:: bash
15
16    yum install libcbor-devel
17
18
19**OS X** users can use `Homebrew <http://brew.sh/>`_:
20
21.. code-block:: bash
22
23    brew install libcbor
24
25For other platforms, you will need to compile it from source.
26
27Building & installing libcbor
28------------------------------
29
30Prerequisites:
31 - C99 compiler
32 - CMake_ 2.8 or newer (might also be called ``cmakesetup``, ``cmake-gui`` or ``ccmake`` depending on the installed version and system)
33 - C build system CMake can target (make, Apple Xcode, MinGW, ...)
34
35.. _CMake: http://cmake.org/
36
37**Configuration options**
38
39A handful of configuration flags can be passed to `cmake`. The following table lists libcbor compile-time directives and several important generic flags.
40
41========================  =======================================================   ======================  =====================================================================================================================
42Option                    Meaning                                                   Default                 Possible values
43------------------------  -------------------------------------------------------   ----------------------  ---------------------------------------------------------------------------------------------------------------------
44``CMAKE_C_COMPILER``      C compiler to use                                         ``cc``                   ``gcc``, ``clang``, ``clang-3.5``, ...
45``CMAKE_INSTALL_PREFIX``  Installation prefix                                       System-dependent         ``/usr/local/lib``, ...
46``BUILD_SHARED_LIBS``     Build as a shared library                                 ``OFF``                  ``ON``, ``OFF``
47``HUGE_FUZZ``             :doc:`Fuzz test </tests>` with 8GB of data                ``OFF``                  ``ON``, ``OFF``
48``SANE_MALLOC``           Assume ``malloc`` will refuse unreasonable allocations    ``OFF``                  ``ON``, ``OFF``
49``COVERAGE``              Generate test coverage instrumentation                    ``OFF``                  ``ON``, ``OFF``
50``WITH_TESTS``            Build unit tests (see :doc:`development`)                 ``OFF``                  ``ON``, ``OFF``
51========================  =======================================================   ======================  =====================================================================================================================
52
53The following configuration options will also be defined as macros [#]_ in ``<cbor/common.h>`` and can therefore be used in client code:
54
55========================  =======================================================   ======================  =====================================================================================================================
56Option                    Meaning                                                   Default                 Possible values
57------------------------  -------------------------------------------------------   ----------------------  ---------------------------------------------------------------------------------------------------------------------
58``CBOR_PRETTY_PRINTER``   Include a pretty-printing routine                         ``ON``                  ``ON``, ``OFF``
59``CBOR_BUFFER_GROWTH``    Factor for buffer growth & shrinking                       ``2``                    Decimals > 1
60========================  =======================================================   ======================  =====================================================================================================================
61
62.. [#] ``ON`` & ``OFF`` will be translated to ``1`` and ``0`` using `cmakedefine <https://cmake.org/cmake/help/v3.2/command/configure_file.html?highlight=cmakedefine>`_.
63
64If you want to pass other custom configuration options, please refer to `<http://www.cmake.org/Wiki/CMake_Useful_Variables>`_.
65
66.. warning::
67    ``CBOR_CUSTOM_ALLOC`` has been `removed <https://github.com/PJK/libcbor/pull/237>`_.
68    Custom allocators (historically a controlled by a build flag) are always enabled.
69
70**Building using make**
71
72CMake will generate a Makefile and other configuration files for the build. As a rule of thumb, you should configure the
73build *outside of the source tree* in order to keep different configurations isolated. If you are unsure where to
74execute the build, just use a temporary directory:
75
76.. code-block:: bash
77
78  cd $(mktemp -d /tmp/cbor_build.XXXX)
79
80Now, assuming you are in the directory where you want to build, build libcbor as a **static library**:
81
82.. code-block:: bash
83
84  cmake -DCMAKE_BUILD_TYPE=Release path_to_libcbor_dir
85  make cbor
86
87... or as a **dynamic library**:
88
89.. code-block:: bash
90
91  cmake -DCMAKE_BUILD_TYPE=Release  -DBUILD_SHARED_LIBS=ON path_to_libcbor_dir
92  make cbor
93
94To install locally:
95
96.. code-block:: bash
97
98  make install
99
100Root permissions are required on most systems when using the default installation prefix.
101
102
103**Portability**
104
105libcbor is highly portable and works on both little- and big-endian systems regardless of the operating system. After building
106on an exotic platform, you might wish to verify the result by running the :doc:`test suite </tests>`. If you encounter any problems, please
107report them to the `issue tracker <https://github.com/PJK/libcbor/issues>`_.
108
109libcbor is known to successfully work on ARM Android devices. Cross-compilation is possible with ``arm-linux-gnueabi-gcc``.
110
111
112Linking with libcbor
113---------------------
114
115If you include and linker paths include the directories to which libcbor has been installed, compiling programs that uses libcbor requires
116no extra considerations.
117
118You can verify that everything has been set up properly by creating a file with the following contents
119
120.. code-block:: c
121
122    #include <cbor.h>
123    #include <stdio.h>
124
125    int main(int argc, char * argv[])
126    {
127        printf("Hello from libcbor %s\n", CBOR_VERSION);
128    }
129
130
131and compiling it
132
133.. code-block:: bash
134
135    cc hello_cbor.c -lcbor -o hello_cbor
136
137
138libcbor also comes with `pkg-config <https://wiki.freedesktop.org/www/Software/pkg-config/>`_ support. If you install libcbor with a custom prefix, you can use pkg-config to resolve the headers and objects:
139
140.. code-block:: bash
141
142    cc $(pkg-config --cflags libcbor) hello_cbor.c $(pkg-config --libs libcbor) -o hello_cbor
143
144
145**A note on linkage**
146
147libcbor is primarily intended to be linked statically. The shared library versioning scheme generally follows `SemVer <https://semver.org/>`_, but is irregular for the 0.X.Y development branch for historical reasons. The following version identifiers are used as a part of the SONAME (Linux) or the dylib `"Compatibility version" <https://developer.apple.com/library/archive/documentation/DeveloperTools/Conceptual/DynamicLibraries/100-Articles/CreatingDynamicLibraries.html>`_ (OS X):
148
149  - 0.Y for the 0.Y.Z branch. Patches are backwards compatible, minor releases are generally not and require re-compilation of any dependent code.
150  - X for the X.Y.Z stable versions starting 1.X.Y. All minor release of the major version are backwards compatible.
151
152.. warning:: Please note that releases up to and including v0.6.0 `may export misleading .so/.dylib version number <https://github.com/PJK/libcbor/issues/52>`_.
153
154
155Troubleshooting
156---------------------
157
158**cbor.h not found**: The headers directory is probably not in your include path. First, verify the installation
159location by checking the installation log. If you used make, it will look something like
160
161.. code-block:: text
162
163    ...
164    -- Installing: /usr/local/include/cbor
165    -- Installing: /usr/local/include/cbor/callbacks.h
166    -- Installing: /usr/local/include/cbor/encoding.h
167    ...
168
169Make sure that ``CMAKE_INSTALL_PREFIX`` (if you provided it) was correct. Including the path path during compilation should suffice, e.g.:
170
171.. code-block:: bash
172
173    cc -I/usr/local/include hello_cbor.c -lcbor -o hello_cbor
174
175
176**cannot find -lcbor during linking**: Most likely the same problem as before. Include the installation directory in the
177linker shared path using ``-R``, e.g.:
178
179.. code-block:: bash
180
181    cc -Wl,-rpath,/usr/local/lib -lcbor -o hello_cbor
182
183**shared library missing during execution**: Verify the linkage using ``ldd``, ``otool``, or similar and adjust the compilation directives accordingly:
184
185.. code-block:: text
186
187    ⇒  ldd hello_cbor
188        linux-vdso.so.1 =>  (0x00007ffe85585000)
189        libcbor.so => /usr/local/lib/libcbor.so (0x00007f9af69da000)
190        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9af65eb000)
191        /lib64/ld-linux-x86-64.so.2 (0x00007f9af6be9000)
192
193**compilation failed**: If your compiler supports C99 yet the compilation has failed, please report the issue to the `issue tracker <https://github.com/PJK/libcbor/issues>`_.
194