mirror of
https://github.com/json-c/json-c.git
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f2e991a341
This patch provides a CMakeLists.txt file to build JSON-C library without relying on auto-tools support. This makes the build a bit more portable and cleaner. It can detect headers and symbols and generate config.h header file based on those detections. It cannot yet handle ctest(1) as the testing itself depends on comparing the output against files. Testing would need some creative abuse of CMake :) This will be provided a few patches later and may possibly involve refactoring test cases. The patch has been tested on GCC 4.8.5 (Linux), GCC 7.2.0 (MinGW) and Microsoft Visual C++ 16.0 (2010?) locally. Also, compiles correctly on Travis CI and AppVeyor without errors.
200 lines
5.7 KiB
Markdown
200 lines
5.7 KiB
Markdown
`json-c`
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========
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1. [Overview and Build Status](#overview)
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2. [Building on Unix](#buildunix)
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3. [Install Prerequisites](#installprereq)
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4. [Building with partial threading support](#buildthreaded)
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5. [Building with CMake](#CMake)
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6. [Linking to libjson-c](#linking)
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7. [Using json-c](#using)
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JSON-C - A JSON implementation in C <a name="overview"></a>
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-----------------------------------
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Build Status
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* [AppVeyor Build](https://ci.appveyor.com/project/hawicz/json-c) 
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* [Travis Build](https://travis-ci.org/json-c/json-c) 
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JSON-C implements a reference counting object model that allows you to easily
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construct JSON objects in C, output them as JSON formatted strings and parse
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JSON formatted strings back into the C representation of JSON objects.
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It aims to conform to [RFC 7159](https://tools.ietf.org/html/rfc7159).
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Building on Unix with `git`, `gcc` and `autotools` <a name="buildunix"></a>
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--------------------------------------------------
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Home page for json-c: https://github.com/json-c/json-c/wiki
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### Prerequisites:
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See also the "Installing prerequisites" section below.
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- `gcc`, `clang`, or another C compiler
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- `libtool>=2.2.6b`
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If you're not using a release tarball, you'll also need:
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- `autoconf>=2.64` (`autoreconf`)
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- `automake>=1.13`
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Make sure you have a complete `libtool` install, including `libtoolize`.
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To generate docs (e.g. as part of make distcheck) you'll also need:
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- `doxygen>=1.8.13`
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### Build instructions:
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`json-c` GitHub repo: https://github.com/json-c/json-c
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```sh
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$ git clone https://github.com/json-c/json-c.git
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$ cd json-c
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$ sh autogen.sh
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```
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followed by
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```sh
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$ ./configure # --enable-threading
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$ make
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$ make install
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```
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To build and run the test programs:
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```sh
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$ make check
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$ make USE_VALGRIND=0 check # optionally skip using valgrind
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```
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Install prerequisites <a name="installprereq"></a>
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-----------------------
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If you are on a relatively modern system, you'll likely be able to install
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the prerequisites using your OS's packaging system.
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### Install using apt (e.g. Ubuntu 16.04.2 LTS)
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```sh
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sudo apt install git
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sudo apt install autoconf automake libtool
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sudo apt install valgrind # optional
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```
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Then start from the "git clone" command, above.
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### Manually install and build autoconf, automake and libtool
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For older OS's that don't have up-to-date version of the packages will
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require a bit more work. For example, CentOS release 5.11, etc...
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```sh
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curl -O http://ftp.gnu.org/gnu/autoconf/autoconf-2.69.tar.gz
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curl -O http://ftp.gnu.org/gnu/automake/automake-1.15.tar.gz
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curl -O http://ftp.gnu.org/gnu/libtool/libtool-2.2.6b.tar.gz
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tar xzf autoconf-2.69.tar.gz
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tar xzf automake-1.15.tar.gz
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tar xzf libtool-2.2.6b.tar.gz
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export PATH=${HOME}/ac_install/bin:$PATH
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(cd autoconf-2.69 && \
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./configure --prefix ${HOME}/ac_install && \
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make && \
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make install)
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(cd automake-1.15 && \
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./configure --prefix ${HOME}/ac_install && \
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make && \
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make install)
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(cd libtool-2.2.6b && \
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./configure --prefix ${HOME}/ac_install && \
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make && \
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make install)
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```
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Building with partial threading support <a name="buildthreaded"></a>
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----------------------------------------
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Although json-c does not support fully multi-threaded access to
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object trees, it has some code to help make use in threaded programs
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a bit safer. Currently, this is limited to using atomic operations for
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json_object_get() and json_object_put().
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Since this may have a performance impact, of at least 3x slower
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according to https://stackoverflow.com/a/11609063, it is disabled by
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default. You may turn it on by adjusting your configure command with:
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--enable-threading
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Separately, the default hash function used for object field keys,
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lh_char_hash, uses a compare-and-swap operation to ensure the randomly
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seed is only generated once. Because this is a one-time operation, it
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is always compiled in when the compare-and-swap operation is available.
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Building with CMake <a name="CMake"></a>
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--------------------
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To use [CMake](https://cmake.org/cmake-tutorial/), build it like:
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```sh
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mkdir build
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cd build
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cmake ../
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make
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```
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CMake can take a few options.
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Variable | Type | Description
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------------------|------|--------------
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BUILD_SHARED_LIBS | Bool | The default build generates static library. Enable this to generate shared (dll/so) library.
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ENABLE_RDRAND | Bool | Enable RDRAND Hardware RNG Hash Seed
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ENABLE_THREADING | Bool | Enable partial threading support
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Pass these options as `-D` on CMake's command-line.
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```sh
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cmake -DBUILD_SHARED_LIBS=On ...
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```
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Linking to `libjson-c` <a name="linking">
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----------------------
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If your system has `pkgconfig`,
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then you can just add this to your `makefile`:
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```make
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CFLAGS += $(shell pkg-config --cflags json-c)
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LDFLAGS += $(shell pkg-config --libs json-c)
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```
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Without `pkgconfig`, you would do something like this:
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```make
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JSON_C_DIR=/path/to/json_c/install
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CFLAGS += -I$(JSON_C_DIR)/include/json-c
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LDFLAGS+= -L$(JSON_C_DIR)/lib -ljson-c
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```
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Using json-c <a name="using">
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------------
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To use json-c you can either include json.h, or preferrably, one of the
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following more specific header files:
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* json_object.h - Core types and methods.
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* json_tokener.h - Methods for parsing and serializing json-c object trees.
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* json_pointer.h - JSON Pointer (RFC 6901) implementation for retrieving
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objects from a json-c object tree.
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* json_object_iterator.h - Methods for iterating over single json_object instances.
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* json_visit.h - Methods for walking a tree of json-c objects.
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* json_util.h - Miscelleanous utility functions.
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For a full list of headers see [files.html](files.html)
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