While Boost.Build V2 is based on the same ideas as Boost.Build V1, some of the syntax was changed, and some new important features were added. This chapter describes most of the changes.
In V1, there were two methods to configure a toolset. One was to
set some environment variable, or use the
-s command line option to set
a variable inside BJam.
Another method was to create a new toolset module that would set
the variables and then invoke the base toolset. Neither method
is necessary now: the
using rule provides a consistent way to
initialize a toolset,
including several versions. See the section called “Configuration” for details.
Probably one of the most important differences in V2 Jamfiles is
the use of project requirements. In V1, if several targets had the same
requirements (for example, a common
#include path), it was necessary to
manually write the requirements or use a helper rule or template target. In V2, the
common properties can be specified with the
attribute, as documented in the section called “Projects”.
also help to simplify Jamfiles.
If a library requires
all clients to use specific
#include paths or macros when compiling
code that depends on the library, that information can be cleanly
The difference between
dll targets in V1 is completely
eliminated in V2. There's only one library target type,
lib, which can create
either static or shared libraries depending on the value of the
feature. If your target should be only built in one way, you
<link>static to its requirements.
The syntax for referring to other targets was changed a bit. While in V1 one would use:
exe a : a.cpp <lib>../foo/bar ;
the V2 syntax is:
exe a : a.cpp ../foo//bar ;
Note that you don't need to specify the type of other target, but the
last element should be separated from the others by a double slash to indicate that
you're referring to target
bar in project
../foo, and not to
The command line syntax in V2 is completely different. For example
bjam -sTOOLS=msvc -sBUILD=release some_target
bjam toolset=msvc variant=release some_target
or, using implicit features, just:
bjam msvc release some_target
See the reference for a complete description of the syntax.