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## Getting Started

This section explains how to setup a system to use this library.

### This Documentation

Programmers should have enough knowledge to use this library after reading the Introduction, Getting Started, and Tutorial sections. The Advanced Topics and Reference sections can be consulted at a later point to gain a more advanced knowledge of the library. All the other sections of this documentation can be considered optional.

Some footnotes are marked by the word "Rationale". They explain reasons behind decisions made during the design and implementation of this library.

In most of the examples presented in this documentation, the Boost.Detail/LightweightTest (`boost/detail/lightweight_test.hpp`) macro `BOOST_TEST` is used to check correctness conditions. The `BOOST_TEST` macro is conceptually similar to `assert` but a failure of the checked condition does not abort the program, instead it makes `boost::report_errors` return a non-zero program exit code. [3]

### Compilers and Platforms

The implementation of this library uses preprocessor and template meta-programming (as supported by Boost.Preprocessor and Boost.MPL), templates with partial specializations and function pointers (similarly to Boost.Function), and automatic type deduction (as supported by Boost.Typeof). The authors originally developed and tested the library on:

1. GNU Compiler Collection (GCC) C++ 4.5.1 on Ubuntu Linux 10.
2. GCC 4.3.4 and 4.5.3 (with and without C++11 features enabled `-std=c++0x`) on Cygwin.
3. Miscrosoft Visual C++ (MSVC) 8.0 on Windows XP and Windows 7.

See the library regressions test results for detailed information on supported compilers and platforms.

### Installation

This library is composed of header files only. Therefore there is no pre-compiled object file which needs to be installed or linked. Programmers can simply instruct the C++ compiler where to find the library header files (`-I` option for GCC, `/I` option for MSVC, etc) and they can start compiling code using this library.

The library implementation uses Boost.Typeof to automatically deduce the types of bound variables (see the Tutorial section). In order to compile code in type-of emulation mode, all types should be properly registered using `BOOST_TYPEOF_REGISTER_TYPE` and `BOOST_TYPEOF_REGISTER_TEMPLATE`, or appropriate Boost.Typeof headers should be included (see the source code of most examples presented in this documentation).

The followings are part of the library private API, they are not documented, and they should not be directly used by programmers: [4]

- Any symbol defined by files within the `boost/local_function/aux_/` or `boost/local_function/detail/` directory (these header files should not be directly included by programmers).
- Any symbol within the `boost::local_function::aux` or `boost::local_function::detail` namespace.
- Any symbol prefixed by `boost_local_function_aux_...` or `boost_local_function_detail_...` (regardless of its namespace).
- Any symbol prefixed by `BOOST_LOCAL_FUNCTION_AUX_...` or `BOOST_LOCAL_FUNCTION_DETAIL_...` (regardless of its namespace).

Some of the library behaviour can be changed at compile-time by defining special configuration macros. If a configuration macro is left undefined, the library will use an appropriate default value for it. All configuration macros are defined in the header file `boost/local_function/config.hpp`. It is strongly recommended not to change the library configuration macro definitions unless strictly necessary.

[3] Rationale. Using Boost.Detail/LightweightTest allows to add the examples to the library regression tests so to make sure that they always compile and run correctly.

[4] Rationale. This library concatenates symbols specified by the programmers (e.g., the local function name) with other symbols (e.g., special prefixes or file line numbers) to make internal symbols with unique names to avoid name clashes. These symbols are separated by the letter "`X`" when they are concatenated so they read more easily during debugging (the underscore character "`_`" could not be used instead of the letter "`X`" because if the original symbols already contained a leading or trailing underscore, the concatenation could result in a symbol with double underscores "`__`" which is reserved by the C++ standard). The "aux" symbols are private to this library while the "detail" symbols may be used within Boost by other libraries but they are still not part of this library public API.