# Getting started

Pre-built Linux packages are available in most mainstream distributions

Ubuntu, Debian, etc.:

    apt-get install libcbor-dev

Fedora, openSUSE, etc.:

    yum install libcbor-devel

OS X users can use Homebrew:

    brew install libcbor

For other platforms, you will need to compile it from source.

## Building & installing libcbor

Prerequisites:

  - C99 compiler

  - CMake 2.8 or newer (might also be called `cmakesetup`, `cmake-gui` or `ccmake` depending on the installed version and system)

  - C build system CMake can target (make, Apple Xcode, MinGW, …)

Configuration options

A handful of configuration flags can be passed to cmake. The following table lists libcbor compile-time directives and several important generic flags.

Option | Meaning | Default | Possible values
`CMAKE_C_COMPILER` | C compiler to use | `cc` | `gcc`, `clang`, `clang-3.5`, …
`CMAKE_INSTALL_PREFIX` | Installation prefix | System-dependent | `/usr/local/lib`, …
`BUILD_SHARED_LIBS` | Build as a shared library | `OFF` | `ON`, `OFF`
`HUGE_FUZZ` | Fuzz test with 8GB of data | `OFF` | `ON`, `OFF`
`SANE_MALLOC` | Assume `malloc` will refuse unreasonable allocations | `OFF` | `ON`, `OFF`
`COVERAGE` | Generate test coverage instrumentation | `OFF` | `ON`, `OFF`
`WITH_TESTS` | Build unit tests (see Development) | `OFF` | `ON`, `OFF`

The following configuration options will also be defined as macros [1] in `<cbor/common.h>` and can therefore be used in client code:

Option | Meaning | Default | Possible values
`CBOR_PRETTY_PRINTER` | Include a pretty-printing routine | `ON` | `ON`, `OFF`
`CBOR_BUFFER_GROWTH` | Factor for buffer growth & shrinking | `2` | Decimals > 1

[1]

`ON` & `OFF` will be translated to `1` and `0` using cmakedefine.

If you want to pass other custom configuration options, please refer to http://www.cmake.org/Wiki/CMake_Useful_Variables.

Warning

`CBOR_CUSTOM_ALLOC` has been removed. Custom allocators (historically a controlled by a build flag) are always enabled.

Building using make

CMake will generate a Makefile and other configuration files for the build. As a rule of thumb, you should configure the build outside of the source tree in order to keep different configurations isolated. If you are unsure where to execute the build, just use a temporary directory:

    cd $(mktemp -d /tmp/cbor_build.XXXX)

Now, assuming you are in the directory where you want to build, build libcbor as a static library:

    cmake -DCMAKE_BUILD_TYPE=Release path_to_libcbor_dir
    make cbor

… or as a dynamic library:

    cmake -DCMAKE_BUILD_TYPE=Release  -DBUILD_SHARED_LIBS=ON path_to_libcbor_dir
    make cbor

To install locally:

    make install

Root permissions are required on most systems when using the default installation prefix.

Portability

libcbor is highly portable and works on both little- and big-endian systems regardless of the operating system. After building on an exotic platform, you might wish to verify the result by running the test suite. If you encounter any problems, please report them to the issue tracker.

libcbor is known to successfully work on ARM Android devices. Cross-compilation is possible with `arm-linux-gnueabi-gcc`.

## Linking with libcbor

If you include and linker paths include the directories to which libcbor has been installed, compiling programs that uses libcbor requires no extra considerations.

You can verify that everything has been set up properly by creating a file with the following contents

    #include <cbor.h>
    #include <stdio.h>

    int main(int argc, char * argv[])
    {
        printf("Hello from libcbor %s\n", CBOR_VERSION);
    }

and compiling it

    cc hello_cbor.c -lcbor -o hello_cbor

libcbor also comes with pkg-config support. If you install libcbor with a custom prefix, you can use pkg-config to resolve the headers and objects:

    cc $(pkg-config --cflags libcbor) hello_cbor.c $(pkg-config --libs libcbor) -o hello_cbor

A note on linkage

libcbor is primarily intended to be linked statically. The shared library versioning scheme generally follows SemVer, 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” (OS X):

> - 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.

> - X for the X.Y.Z stable versions starting 1.X.Y. All minor release of the major version are backwards compatible.

Warning

Please note that releases up to and including v0.6.0 may export misleading .so/.dylib version number.

## Troubleshooting

cbor.h not found: The headers directory is probably not in your include path. First, verify the installation location by checking the installation log. If you used make, it will look something like

    ...
    -- Installing: /usr/local/include/cbor
    -- Installing: /usr/local/include/cbor/callbacks.h
    -- Installing: /usr/local/include/cbor/encoding.h
    ...

Make sure that `CMAKE_INSTALL_PREFIX` (if you provided it) was correct. Including the path path during compilation should suffice, e.g.:

    cc -I/usr/local/include hello_cbor.c -lcbor -o hello_cbor

cannot find -lcbor during linking: Most likely the same problem as before. Include the installation directory in the linker shared path using `-R`, e.g.:

    cc -Wl,-rpath,/usr/local/lib -lcbor -o hello_cbor

shared library missing during execution: Verify the linkage using `ldd`, `otool`, or similar and adjust the compilation directives accordingly:

    ⇒  ldd hello_cbor
        linux-vdso.so.1 =>  (0x00007ffe85585000)
        libcbor.so => /usr/local/lib/libcbor.so (0x00007f9af69da000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9af65eb000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f9af6be9000)

compilation failed: If your compiler supports C99 yet the compilation has failed, please report the issue to the issue tracker.