Using Autotools in the LTP Build Process
========================================

The Linux Test Project (LTP) uses the GNU Autotools build system to configure and compile the source code. The key components of Autotools are ``autoconf``, ``autoreconf``, and ``./configure``. Below is an explanation of their purpose and a typical workflow for building LTP.

Purpose of Autotools Commands
-----------------------------

1. **autoconf**
   - Generates the ``configure`` script from ``configure.ac`` (or ``configure.in``).
   - The ``configure.ac`` file contains macros that test for system features, libraries, and headers required for the build.

2. **autoreconf**
   - A wrapper script that runs all the necessary Autotools commands (e.g., ``autoconf``, ``automake``, ``aclocal``, etc.) in the correct order.
   - Useful when the build system needs to be regenerated from scratch.

3. **./configure**
   - A shell script generated by ``autoconf`` that checks the system for dependencies, libraries, and headers.
   - Generates ``Makefile`` and other configuration files based on the system environment.

Typical Workflow for Building LTP
---------------------------------

Below is a regular session or workflow for building LTP using Autotools:

1. **Clone the LTP Repository**
   - Start by cloning the LTP repository from GitHub.

   .. code-block:: bash

      git clone https://github.com/linux-test-project/ltp.git
      cd ltp

2. **Generate the Build System**
   - If the ``configure`` script is not present or needs to be regenerated, use ``autoreconf``.

   .. code-block:: bash

      autoreconf -fvi

   - This command ensures that all necessary Autotools scripts are up-to-date.

3. **Run the Configure Script**
   - Execute the ``./configure`` script to check for system dependencies and generate the ``Makefile``.

   .. code-block:: bash

      ./configure

   - You can specify additional options, such as installation prefix:

   .. code-block:: bash

      ./configure --prefix=/opt/ltp

4. **Compile the Source Code**
   - Use ``make`` to compile the source code.

   .. code-block:: bash

      make

5. **Install the Compiled Binaries**
   - Install the compiled binaries to the specified prefix (e.g., ``/opt/ltp``).

   .. code-block:: bash

      make install

6. **Run LTP Tests**
   - After installation, you can run the LTP tests from the installation directory.

   .. code-block:: bash

      /opt/ltp/runltp

Example Session
---------------

Here’s an example session for building LTP:

.. code-block:: bash

   # Clone the LTP repository
   git clone https://github.com/linux-test-project/ltp.git
   cd ltp

   # Regenerate the build system
   autoreconf -fvi

   # Configure the build
   ./configure --prefix=/opt/ltp

   # Compile the source code
   make

   # Install the binaries
   make install

   # Run LTP tests
   /opt/ltp/runltp

Summary
-------

- ``autoconf`` generates the ``configure`` script from ``configure.ac``.
- ``autoreconf`` regenerates the entire build system.
- ``./configure`` checks for system dependencies and generates ``Makefile``.
- The typical workflow involves cloning the repository, regenerating the build system, configuring, compiling, and installing the software.