MPI_CHAR
PI_BYTE, MPI_SHORT, MPI_INT, MPI_LONG, MPI_FLOAT, MPI_DOUBLE, MPI_UNSIGNED_CHAR, MPI_UNSIGNED_SHORT, MPI_UNSIGNED, MPI_UNSIGNED_LONG, MPI_LONG_DOUBLE - MPI C Datatypes 
- MPI_CHAR  
-  char
- MPI_BYTE  
-  See standard; like unsigned char
- MPI_SHORT  
-  short
- MPI_INT    
-  int
- MPI_LONG  
-  long
- MPI_FLOAT  
-  float
- MPI_DOUBLE  
-  double
- MPI_UNSIGNED_CHAR  
-  unsigned char
- MPI_UNSIGNED_SHORT  
-  unsigned short
- MPI_UNSIGNED  
-  unsigned int
- MPI_UNSIGNED_LONG  
-  unsigned long
- MPI_LONG_DOUBLE   
-  long double (some systems may not implement)
Data types
Note that the Fortran types should only be used in Fortran programs,
and the C types should only be used in C programs.  For example,
it is in error to use MPI_INT for a Fortran INTEGER.
Datatypes are of type MPI_Datatype in C and of tyep INTEGER in Fortran.
Location:/home/MPI/mansrc/mpiconsts.txt