id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
10768	Changes to Optional cause compilation errors in adjacency_list/named_graph since 1.56.0	tastky <tastky@…>	Fernando Cacciola	"Getting this since 1.56.0, now using 1.57.0 and GCC 4.9.2 on Arch. Code had compiled fine for months.

I never use anything from Optional in my code myself, nor does GCC mention any relevant lines in it, so I'm guessing the bug lies within boost.

{{{
In file included from /usr/include/boost/optional.hpp:15:0,
                 from /usr/include/boost/graph/named_graph.hpp:21,
                 from /usr/include/boost/graph/adjacency_list.hpp:45,
                 from ./Graph.h:6,
/usr/include/boost/optional/optional.hpp:1062:33: error: macro ""value_or"" requires 2 arguments, but only 1 given
     value_type value_or ( U&& v ) const&
                                 ^
/usr/include/boost/optional/optional.hpp:1071:33: error: macro ""value_or"" requires 2 arguments, but only 1 given
     value_type value_or ( U&& v ) &&
}}}

This repeats wherever adjacency_list.hpp is included. For each of these I then also get later…

{{{
/usr/include/boost/optional/optional.hpp:1062:35: error: expected initializer before ‘const’
     value_type value_or ( U&& v ) const&
                                   ^
/usr/include/boost/optional/optional.hpp:1071:35: error: expected initializer before ‘&&’ token
     value_type value_or ( U&& v ) &&
}}}

… with again no further context."	Bugs	closed	To Be Determined	optional	Boost 1.57.0	Regression	invalid	gcc optional graph bgl value_or adjacency_list