diff --git a/include/mpi.h.in b/include/mpi.h.in
index 3324463b14..7d35af3b22 100644
--- a/include/mpi.h.in
+++ b/include/mpi.h.in
@@ -535,6 +535,7 @@ OMPI_DECLSPEC extern struct ompi_datatype_t ompi_mpi_short, ompi_mpi_long;
 OMPI_DECLSPEC extern struct ompi_datatype_t ompi_mpi_float, ompi_mpi_double;
 OMPI_DECLSPEC extern struct ompi_datatype_t ompi_mpi_long_double;
 OMPI_DECLSPEC extern struct ompi_datatype_t ompi_mpi_cplex, ompi_mpi_packed;
+OMPI_DECLSPEC extern struct ompi_datatype_t ompi_mpi_signed_char;
 OMPI_DECLSPEC extern struct ompi_datatype_t ompi_mpi_unsigned_char;
 OMPI_DECLSPEC extern struct ompi_datatype_t ompi_mpi_unsigned_short;
 OMPI_DECLSPEC extern struct ompi_datatype_t ompi_mpi_unsigned, ompi_mpi_datatype_null;