Mateusz Loskot wrote:
Steven Watanabe wrote:
Mateusz Loskot wrote:
For 1st example for the case 1), in trunk/libs/accumulators/example/Jamfile.v2, Boost headers are located by relative path and mysterious $(BOOST_ROOT)
exe example : main.cpp : <include>../../.. <include>$(BOOST_ROOT) ;
<include>$(BOOST_ROOT) can be replaced with <dependency>/boost//headers
Yet another option I've just learned, but...
What is the difference between using headers-only library by specifying this requirement using <source> and <dependency>?
The manual says:
"(...)a dependency on the target (...) (so it will be brought up-to-date whenever the target being declared is). The dependency is not used in any other way."
What does bringing up-to-date mean for headers-only? Also, the "not used in any other way" suggests to me that it does not implicitly update <include> directories.
Actually, for /boost//headers there's no difference between <source> and <dependency>. Every single metatarget in Boost.Build, when built, produces two things: - actual targets (corresponding to files) - set of properties that must be propagated to dependents. These are known as usage requirements. Now, there are three predefined build properties: 1. <source> tries to consume the produced targets, and adds usage requirements. 2. <dependency> sets a dependency on the produced targets, and also adds usage requirements. 3. <use> only sets usage requirements Now, because the 'headers' metatarget never produces any real file, only usage requirements, all three are exactly the same. - Volodya