...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Copyright © 2001-2007 Beman Dawes, Vesa Karvonen, John Maddock
Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Table of Contents
Boost comes already configured for most common compilers and platforms; you should be able to use boost "as is". Since the compiler is configured separately from the standard library, the default configuration should work even if you replace the compiler's standard library with a third-party standard library (like STLport).
Using boost "as is" without trying to reconfigure is the recommended method for using boost. You can, however, run the configure script if you want to, and there are regression tests provided that allow you to test the current boost configuration with your particular compiler setup.
Boost library users can request support for additional compilers or platforms by visiting our Github and submitting a support request.
Boost library implementations access configuration macros via
#include <boost/config.hpp>
While Boost library users are not required to include that file directly, or use those configuration macros, such use is acceptable. The configuration macros are documented as to their purpose, usage, and limitations which makes them usable by both Boost library and user code.
Boost informational or helper macros are designed for use by Boost users as well as for our own internal use. Note however, that the feature test and defect test macros were designed for internal use by Boost libraries, not user code, so they can change at any time (though no gratuitous changes are made to them). Boost library problems resulting from changes to the configuration macros are caught by the Boost regression tests, so the Boost libraries are updated to account for those changes. By contrast, Boost library user code can be adversely affected by changes to the macros without warning. The best way to keep abreast of changes to the macros used in user code is to monitor the discussions on the Boost developers list.
Important | |
---|---|
This configure script only sets up the Boost headers for use with a particular compiler. It has no effect on Boost.Build, or how the libraries are built. |
If you know that boost is incorrectly configured for your particular setup,
and you are on a UNIX like platform, then you may want to try and improve
things by running the boost configure script. From a shell command prompt
you will need to cd into <boost-root>/libs/config/
and type:
sh ./configure
you will see a list of the items being checked as the script works its way through the regression tests. Note that the configure script only really auto-detects your compiler if it's called g++, c++ or CC. If you are using some other compiler you will need to set one or more of the following environment variables:
Variable |
Description |
---|---|
CXX |
The name of the compiler, for example |
CXXFLAGS |
The compiler flags to use, for example |
LDFLAGS |
The linker flags to use, for example |
LIBS |
Any libraries to link in, for example |
For example to run the configure script with HP aCC, you might use something like:
export CXX="aCC" export CXXFLAGS="-Aa -DAportable -D__HPACC_THREAD_SAFE_RB_TREE \ -DRWSTD_MULTI_THREAD -DRW_MULTI_THREAD -D_REENTRANT -D_THREAD_SAFE" export LDFLAGS="-DAportable" export LIBS="-lpthread" sh ./configure
However you run the configure script, when it finishes you will find a new
header -user.hpp
- located in the <boost-root>/libs/config/
directory. Note that configure does not install this
header into your boost include path by default. This header contains
all the options generated by the configure script, plus a header-section
that contains the user settable options from the default version of <boost/config/user.hpp>
(located under <boost-root>/boost/config/
).
There are two ways you can use this header:
/boost/config/
so that it replaces the default user.hpp
provided by boost. This option allows only one configure-generated setup;
boost developers should avoid this option, as it incurs the danger of
accidentally committing a configure-modified <boost/config/user.hpp>
to the svn repository (something you will not be thanked for!).
BOOST_USER_CONFIG
to point to it. For
example create a new sub-directory <boost-root>/boost/config/
user/
, and copy the header there; for example
as multithread-gcc-config.hpp
. Then, when compiling add the command
line option: -DBOOST_USER_CONFIG="<boost/config/user/multithread-gcc-config.hpp>"
,
and boost will use the new configuration header. This option allows you
to generate more than one configuration header, and to keep them separate
from the boost source - so that updates to the source do not interfere
with your configuration.
There are some configuration-options that represent user choices, rather
than compiler defects or platform specific options. These are listed in
<boost/config/user.hpp>
and at the start of a configure-generated user.hpp
header.
You can define these on the command line, or by editing <boost/config/user.hpp>
, they are listed in the following table:
Macro |
Description |
---|---|
|
When defined, it should point to the name of the user configuration
file to include prior to any boost configuration files. When not
defined, defaults to |
|
When defined, it should point to the name of the compiler configuration
file to use. Defining this cuts out the compiler selection logic,
and eliminates the dependency on the header containing that logic.
For example if you are using gcc, then you could define BOOST_COMPILER_CONFIG
to |
|
When defined, it should point to the name of the standard library
configuration file to use. Defining this cuts out the standard
library selection logic, and eliminates the dependency on the header
containing that logic. For example if you are using STLport, then
you could define |
|
When defined, it should point to the name of the platform configuration
file to use. Defining this cuts out the platform selection logic,
and eliminates the dependency on the header containing that logic.
For example if you are compiling on linux, then you could define
|
|
When defined, no compiler configuration file is selected or included,
define when the compiler is fully conformant with the standard,
or where the user header (see |
|
When defined, no standard library configuration file is selected
or included, define when the standard library is fully conformant
with the standard, or where the user header (see |
|
When defined, no platform configuration file is selected or included,
define when the platform is fully conformant with the standard
(and has no useful extra features), or where the user header (see
|
|
Equivalent to defining all of |
|
The normal behavior for compiler versions that are newer than the last known version, is to assume that they have all the same defects as the last known version. By setting this define, then compiler versions that are newer than the last known version are assumed to be fully conforming with the standard. This is probably most useful for boost developers or testers, and for those who want to use boost to test beta compiler versions. |
|
When this flag is set, if the config finds anything unknown, then it will stop with a #error rather than continue. Boost regression testers should set this define, as should anyone who wants to quickly check whether boost is supported on their platform. |
|
When defined, disables threading support, even if the compiler in its current translation mode supports multiple threads. |
|
When defined, disables the use of Win32 specific API's, even when
these are available. Also has the effect of setting |
|
Stops boost headers from including any prefix/suffix headers that normally control things like struct packing and alignment. |
|
A prefix header to include in place of whatever boost.config would normally select, any replacement should set up struct packing and alignment options as required. |
|
A suffix header to include in place of whatever boost.config would normally select, any replacement should undo the effects of the prefix header. |
|
Forces all libraries that have separate source, to be linked as
dll's rather than static libraries on Microsoft Windows (this macro
is used to turn on |
|
Forces library "whatever" to be linked as a dll rather
than a static library on Microsoft Windows: replace the WHATEVER
part of the macro name with the name of the library that you want
to dynamically link to, for example use |
|
Tells the config system not to automatically select which libraries to link against. Normally if a compiler supports #pragma lib, then the correct library build variant will be automatically selected and linked against, simply by the act of including one of that library's headers. This macro turns that feature off. |
|
Tells the config system not to automatically select which library
to link against for library "whatever", replace WHATEVER
in the macro name with the name of the library; for example |
|
Causes the auto-linking code to output diagnostic messages indicating the name of the library that is selected for linking. |
|
If you built Boost using the |
|
Overrides the name of the toolset part of the name of library being linked to; note if defined this must be defined to a quoted string literal, for example "abc". |
By setting various macros on the compiler command line or by editing <boost/config/user.hpp>, the boost configuration setup can be optimised in a variety of ways.
Boost's configuration is structured so that the user-configuration is included
first (defaulting to <boost/config/user.hpp>
if BOOST_USER_CONFIG
is not
defined). This sets up any user-defined policies, and gives the user-configuration
a chance to influence what happens next.
Next the compiler, standard library, and platform configuration files are
included. These are included via macros (BOOST_COMPILER_CONFIG
etc, see user settable macros),
and if the corresponding macro is undefined then a separate header that detects
which compiler/standard library/platform is in use is included in order to
set these. The config can be told to ignore these headers altogether if the
corresponding BOOST_NO_XXX
macro is set (for example BOOST_NO_COMPILER_CONFIG
to disable including any compiler configuration file - see
user settable macros).
Finally the boost configuration header, includes <boost/config/detail/suffix.hpp>; this header contains any boiler plate configuration code - for example where one boost macro being set implies that another must be set also.
The following usage examples represent just a few of the possibilities:
Lets suppose that we're building boost with Visual C++ 6, and STLport 4.0.
Lets suppose also that we don't intend to update our compiler or standard
library any time soon. In order to avoid breaking dependencies when we
update boost, we may want to "freeze" our configuration headers,
so that we only have to rebuild our project if the boost code itself has
changed, and not because the boost config has been updated for more recent
versions of Visual C++ or STLport. We'll start by realising that the configuration
files in use are: <boost/config/compiler/visualc.hpp>
for the compiler, <boost/config/stdlib/stlport.hpp>
for the standard library, and
<boost/config/platform/win32.hpp>
for the platform. Next we'll
create our own private configuration directory: boost/config/mysetup/
, and copy the configuration files into
there. Finally, open up <boost/config/user.hpp>
and edit the following defines:
#define BOOST_COMPILER_CONFIG "boost/config/mysetup/visualc.hpp" #define BOOST_STDLIB_CONFIG "boost/config/mysetup/stlport.hpp" #define BOOST_USER_CONFIG "boost/config/mysetup/win32.hpp"
Now when you use boost, its configuration header will go straight to our "frozen" versions, and ignore the default versions, you will now be insulated from any configuration changes when you update boost. This technique is also useful if you want to modify some of the boost configuration files; for example if you are working with a beta compiler release not yet supported by boost.
Lets suppose that you're using boost with a compiler that is fully conformant
with the standard; you're not interested in the fact that older versions
of your compiler may have had bugs, because you know that your current
version does not need any configuration macros setting. In a case like
this, you can define BOOST_NO_COMPILER_CONFIG
either on the command line, or in <boost/config/user.hpp>,
and miss out the compiler configuration header altogether (actually you
miss out two headers, one which works out what the compiler is, and one
that configures boost for it). This has two consequences: the first is
that less code has to be compiled, and the second that you have removed
a dependency on two boost headers.
If you are working on a unix-like platform then you can use the configure script to generate a "frozen" configuration based on your current compiler setup - see using the configure script for more details.
The boost configuration library provides a full set of regression test programs
under the <boost-root>/boost/config/
test/
sub-directory:
File |
Description |
---|---|
|
Prints out a detailed description of your compiler/standard library/platform setup, plus your current boost configuration. The information provided by this program is useful in setting up the boost configuration files. If you report that boost is incorrectly configured for your compiler/library/platform then please include the output from this program when reporting the changes required. |
|
A monolithic test program that includes most of the individual test cases. This provides a quick check to see if boost is correctly configured for your compiler/library/platform. |
|
Tests your standard library's |
|
Individual compiler defect test files. Each of these should compile,
if one does not then the corresponding |
|
Individual compiler defect test files. Each of these should not
compile, if one does then the corresponding |
|
Individual feature test files. If one of these does not compile
then the corresponding |
|
Individual feature test files. If one of these does compile then
the corresponding |
Although you can run the configuration regression tests as individual test files, there are rather a lot of them, so there are a couple of shortcuts to help you out:
Alternatively you can run the configure script like this:
./configure --enable-test
in which case the script will test the current configuration rather than creating a new one from scratch.
If you are reporting the results of these tests for a new platform/library/compiler
then please include a log of the full compiler output, the output from config_info.cpp
, and the pass/fail test results.
Last revised: December 02, 2021 at 06:52:40 GMT |