[mpich-discuss] Reduction with MPI_CHAR

MPI 3.1 Chapter 5.9.3 reads "MPI_CHAR, MPI_WCHAR, and MPI_CHARACTER (which represent printable characters) cannot be used in reduction operations". But the following code with MPICH does not abort. #include <mpi.h> #include <stdlib.h> int main(int argc, char* argv[]) { char a ='A',b; MPI_Init(&argc,&argv); if(MPI_Allreduce(&a,&b,1,MPI_CHAR,MPI_SUM,MPI_COMM_WORLD)) abort(); MPI_Finalize(); } --Junchao Zhang