id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
2594	Bug into all_reduce	micdestefano@…	Douglas Gregor	"Good Morning.[[BR]]

I've found a bug into the file[[BR]][[BR]]
`boost/mpi/collectives/all_reduce.hpp`[[BR]][[BR]]
At line 36 you should change[[BR]][[BR]]
`is_mpi_op<Op, T>::op()`[[BR]]
[[BR]]
into[[BR]]
[[BR]]
`(is_mpi_op<Op, T>::op())`[[BR]]
[[BR]]
i.e. add a couple of parentheses around the expression. Without those parentheses, this build error occurs:[[BR]]
[[BR]]
`error: macro ""MPI_Allreduce"" passed 7 arguments, but takes just 6`[[BR]]
[[BR]]
because the comma that separates template parameters confuses the preprocessor.[[BR]]
[[BR]]
I've noticed that the bug is still present into the Boost.MPI development version.[[BR]]
[[BR]]
My compiler is gcc 4.1.2.[[BR]]
[[BR]]
Thank you in advance.[[BR]]
Michele De Stefano"	Bugs	closed	Boost 1.39.0	mpi	Boost Development Trunk	Problem	fixed	all_reduce,	Matthias Troyer