An implementation is allowed to implement MPI_WTIME, MPI_WTICK, PMPI_WTIME, PMPI_WTICK, and the handle-conversion functions ( MPI_Group_f2c, etc.) in Section Transfer of Handles , and no others, as macros in C.
 
 
 
 Advice  
        to implementors.  
 
Implementors should document which routines are implemented as macros.  
 ( End of advice to implementors.) 
 
 
 
 Advice to users.  
 
If these routines are implemented as macros, they will not work with the  MPI  
profiling interface.  
 ( End of advice to users.)