[Boost-bugs] [Boost C++ Libraries] #12555: Graph headers are not self-contained

Subject: [Boost-bugs] [Boost C++ Libraries] #12555: Graph headers are not self-contained
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-10-26 21:45:17

#12555: Graph headers are not self-contained
------------------------------+----------------------
 Reporter:  gromer@…          |      Owner:  jewillco
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  graph
  Version:  Boost 1.60.0      |   Severity:  Problem
 Keywords:                    |
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 Many BGL header files are not self-contained, meaning that they will not
 compile if `#include`d into a translation unit that doesn't `#include`
 anything else. For example, `boost/graph/bandwidth.hpp` refers to
 `vertex_index`, but does not `#include boost/graph/properties.hpp`, the
 header which declares `vertex_index`.

 Among other things, this prevents BGL from being adapted to take advantage
 of C++ modules (see http://clang.llvm.org/docs/Modules.html), because
 modules require headers to be self-contained.

 Attached is a patch (against 1.60.0) to correct these problems, usually by
 adding missing `#include`s. The change to `howard_cycle_ratio.hpp` is
 slightly more subtle: the problem there is that the code refers to
 `boost::num_edges(g)`, but doesn't `#include` a header that declares that
 function. However, the choice of the right header to `#include` depends on
 the type `Graph` of `g`, which is a template parameter. This points to the
 real problem: this code should be calling `num_edges(g)` unqualified, so
 that it uses argument-dependent lookup to find the `num_edges()` overload
 in the namespace of `Graph`, rather than restricting itself to the
 overloads defined in namespace `boost`.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12555>
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