Table 1 lists all of the C++ predefined MPI datatypes and their corresponding C and C++ datatypes, Table 2 lists all of the Fortran predefined MPI datatypes and their corresponding Fortran 77 datatypes. Table 3 lists the C++ names for all other MPI datatypes.
MPI::BYTE and MPI::PACKED conform to the same restrictions as MPI_BYTE and MPI_PACKED, listed in Sections 3.2.2 and 3.13 of MPI-1, respectively.
| MPI datatype | C datatype | C++ datatype |
| MPI::CHAR | char | char |
| MPI::WCHAR | wchar_t | wchar_t |
| MPI::SHORT | signed short | signed short |
| MPI::INT | signed int | signed int |
| MPI::LONG | signed long | signed long |
| MPI::SIGNED_CHAR | signed char | signed char |
| MPI::UNSIGNED_CHAR | unsigned char | unsigned char |
| MPI::UNSIGNED_SHORT | unsigned short | unsigned short |
| MPI::UNSIGNED | unsigned int | unsigned int |
| MPI::UNSIGNED_LONG | unsigned long | unsigned long int |
| MPI::FLOAT | float | float |
| MPI::DOUBLE | double | double |
| MPI::LONG_DOUBLE | long double | long double |
| MPI::BOOL | bool | |
| MPI::COMPLEX | Complex<float> | |
| MPI::DOUBLE_COMPLEX | Complex<double> | |
| MPI::LONG_DOUBLE_COMPLEX | Complex<long double> | |
| MPI::BYTE | ||
| MPI::PACKED | ||
| MPI datatype | Fortran datatype |
| MPI::CHARACTER | CHARACTER(1) |
| MPI::INTEGER | INTEGER |
| MPI::REAL | REAL |
| MPI::DOUBLE_PRECISION | DOUBLE PRECISION |
| MPI::LOGICAL | LOGICAL |
| MPI::F_COMPLEX | COMPLEX |
| MPI::BYTE | |
| MPI::PACKED | |
| MPI datatype | Description |
| MPI::FLOAT_INT | C/C++ reduction type |
| MPI::DOUBLE_INT | C/C++ reduction type |
| MPI::LONG_INT | C/C++ reduction type |
| MPI::TWOINT | C/C++ reduction type |
| MPI::SHORT_INT | C/C++ reduction type |
| MPI::LONG_DOUBLE_INT | C/C++ reduction type |
| MPI::LONG_LONG | Optional C/C++ type |
| MPI::UNSIGNED_LONG_LONG | Optional C/C++ type |
| MPI::TWOREAL | Fortran reduction type |
| MPI::TWODOUBLE_PRECISION | Fortran reduction type |
| MPI::TWOINTEGER | Fortran reduction type |
| MPI::F_DOUBLE_COMPLEX | Optional Fortran type |
| MPI::INTEGER1 | Explicit size type |
| MPI::INTEGER2 | Explicit size type |
| MPI::INTEGER4 | Explicit size type |
| MPI::INTEGER8 | Explicit size type |
| MPI::REAL4 | Explicit size type |
| MPI::REAL8 | Explicit size type |
| MPI::REAL16 | Explicit size type |
The following table defines groups of MPI predefined datatypes:
C integer: MPI::INT, MPI::LONG, MPI::SHORT,
MPI::UNSIGNED_SHORT, MPI::UNSIGNED,
MPI::UNSIGNED_LONG, MPI::SIGNED_CHAR,
MPI::UNSIGNED_CHAR
Fortran integer: MPI::INTEGER
Floating point: MPI::FLOAT, MPI::DOUBLE, MPI::REAL,
MPI::DOUBLE_PRECISION,
MPI::LONG_DOUBLE
Logical: MPI::LOGICAL, MPI::BOOL
Complex: MPI::F_COMPLEX, MPI::COMPLEX,
MPI::F_DOUBLE_COMPLEX,
MPI::DOUBLE_COMPLEX,
MPI::LONG_DOUBLE_COMPLEX
Byte: MPI::BYTE
Valid datatypes for each reduction operation is specified below in terms of the groups defined above.
Op Allowed Types
MPI::MAX, MPI::MIN C integer, Fortran integer, Floating point
MPI::SUM, MPI::PROD C integer, Fortran integer,
Floating point, Complex
MPI::LAND, MPI::LOR, MPI::LXOR C integer, Logical
MPI::BAND, MPI::BOR, MPI::BXOR C integer, Fortran integer, Byte
MPI::MINLOC and MPI::MAXLOC perform just as their C and Fortran counterparts; see Section 4.9.3 in MPI-1.