Constants

Meaning of MPI's defined constants

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, type INTEGER in Fortran, and Type(MPI_Datatype) in Fortran08

C datatypes

MPI_CHAR
char
MPI_SIGNED_CHAR
signed char
MPI_UNSIGNED_CHAR
unsigned char
MPI_BYTE
See standard; like unsigned char
MPI_WCHAR
wide character (wchar_t)
MPI_SHORT
short
MPI_UNSIGNED_SHORT
unsigned short
MPI_INT
int
MPI_UNSIGNED
unsigned int
MPI_LONG
long
MPI_UNSIGNED_LONG
unsigned long
MPI_LONG_LONG_INT
long long
MPI_LONG_LONG
synonyn for MPI_LONG_LONG_INT
MPI_UNSIGNED_LONG_LONG
unsigned long long
MPI_FLOAT
float
MPI_DOUBLE
double
MPI_LONG_DOUBLE
long double (some systems may not implement this)
MPI_INT8_T
int8_t
MPI_INT16_T
int16_t
MPI_INT32_T
int32_t
MPI_INT64_T
int64_t
MPI_UINT8_T
uint8_t
MPI_UINT16_T
uint16_t
MPI_UINT32_T
uint32_t
MPI_UINT64_T
uint64_t
MPI_C_BOOL
_Bool
MPI_C_FLOAT_COMPLEX
float _Complex
MPI_C_COMPLEX
float _Complex
MPI_C_DOUBLE_COMPLEX
double _Complex
MPI_C_LONG_DOUBLE_COMPLEX
long double _Complex

The following are datatypes for the MPI functions MPI_MAXLOC and MPI_MINLOC.

MPI_FLOAT_INT
struct { float, int }
MPI_LONG_INT
struct { long, int }
MPI_DOUBLE_INT
struct { double, int }
MPI_SHORT_INT
struct { short, int }
MPI_2INT
struct { int, int }
MPI_LONG_DOUBLE_INT
struct { long double, int }; this is an optional type, and may be set to MPI_DATATYPE_NULL

Special datatypes for C and Fortran

MPI_PACKED
For MPI_Pack and MPI_Unpack
MPI_UB
For MPI_Type_struct; an upper-bound indicator. Removed in MPI 3
MPI_LB
For MPI_Type_struct; a lower-bound indicator. Removed in MPI 3

Fortran datatypes

MPI_REAL
REAL
MPI_INTEGER
INTEGER
MPI_LOGICAL
LOGICAL
MPI_DOUBLE_PRECISION
DOUBLE PRECISION
MPI_COMPLEX
COMPLEX
MPI_DOUBLE_COMPLEX
complex*16 (or complex*32) where supported.

The following datatypes are optional

MPI_INTEGER1
integer*1 if supported
MPI_INTEGER2
integer*2 if supported
MPI_INTEGER4
integer*4 if supported
MPI_INTEGER8
integer*8 if supported
MPI_INTEGER16
integer*16 if supported
MPI_REAL4
real*4 if supported
MPI_REAL8
real*8 if supported
MPI_REAL16
real*16 if supported
MPI_COMPLEX8
complex*8 if supported
MPI_COMPLEX16
complex*16 if supported
MPI_COMPLEX32
complex*32 if supported

The following are datatypes for the MPI functions MPI_MAXLOC and MPI_MINLOC. In Fortran, these datatype always consist of two elements of the same Fortran type.

MPI_2INTEGER
INTEGER,INTEGER
MPI_2REAL
REAL, REAL
MPI_2DOUBLE_PRECISION
DOUBLE PRECISION, DOUBLE PRECISION

MPI Datatypes for MPI Types

MPI_AINT
Datatype for an MPI_Aint
MPI_OFFSET
Datatype for an MPI_Offset
MPI_COUNT
Datatype for an MPI_Count

MPI Datatype Combiner Names

MPI_COMBINER_NAMED
a named predefined datatype
MPI_COMBINER_DUP
MPI_TYPE_DUP
MPI_COMBINER_CONTIGUOUS
MPI_TYPE_CONTIGUOUS
MPI_COMBINER_VECTOR
MPI_TYPE_VECTOR
MPI_COMBINER_HVECTOR_INTEGER
Removed in MPI-3
MPI_COMBINER_HVECTOR
MPI_TYPE_CREATE_HVECTOR
MPI_COMBINER_INDEXED
MPI_TYPE_INDEXED
MPI_COMBINER_HINDEXED_INTEGER
Removed in MPI-3
MPI_COMBINER_HINDEXED
MPI_TYPE_CREATE_HINDEXED
MPI_COMBINER_INDEXED_BLOCK
MPI_TYPE_CREATE_INDEXED_BLOCK
MPI_COMBINER_STRUCT_INTEGER
Removed in MPI-3
MPI_COMBINER_STRUCT
MPI_TYPE_CREATE_STRUCT
MPI_COMBINER_SUBARRAY
MPI_TYPE_CREATE_SUBARRAY
MPI_COMBINER_DARRAY
MPI_TYPE_CREATE_DARRAY
MPI_COMBINER_F90_REAL
MPI_TYPE_CREATE_F90_REAL
MPI_COMBINER_F90_COMPLEX
MPI_TYPE_CREATE_F90_COMPLEX
MPI_COMBINER_F90_INTEGER
MPI_TYPE_CREATE_F90_INTEGER
MPI_COMBINER_RESIZED
MPI_TYPE_CREATE_RESIZED
MPI_COMBINER_HINDEXED_BLOCK
MPI_TYPE_CREATE_HINDEXED_BLOCK

MPI Datatype Type Classes

MPI Type classes used with routines to return Fortran types with defined precision and range
MPI_TYPECLASS_REAL
REAL
MPI_TYPECLASS_INTEGER
INTEGER
MPI_TYPECLASS_COMPLEX
COMPLEX

MPI Darray and Subarray Values

These values are used to create a datatype with the DARRAY and SUBARRAY constructors.
MPI_ORDER_C
Row-major order (as used by C)
MPI_ORDER_FORTRAN
Column-major order (as used by Fortran)
MPI_DISTRIBUTE_BLOCK
Block distribution
MPI_DISTRIBUTE_CYCLIC
Cyclic distribution
MPI_DISTRIBUTE_NONE
This dimension is not distributed
MPI_DISTRIBUTE_DFLT_DARG
Use the default distribution

Communicators

Communicators are of type MPI_Comm in C, INTEGER in Fortran, and Type(MPI_Comm) in Fortran08
MPI_COMM_WORLD
Contains all of the processes
MPI_COMM_SELF
Contains only the calling process

Kind of communicator for 'MPI_COMM_SPLIT_TYPE'

MPI_COMM_TYPE_SHARED
All processes that can share memory are grouped into the same communicator.

Groups

Groups are of type MPI_Group in C, INTEGER in Fortran, and Type(MPI_Group) in Fortran08

MPI_GROUP_EMPTY
A group containing no members.

Results of the compare operations on groups and communicators

MPI_IDENT
Identical
MPI_CONGRUENT
(only for MPI_COMM_COMPARE) The groups are identical
MPI_SIMILAR
Same members, but in a different order
MPI_UNEQUAL
Different

Collective operations

The collective combination operations (e.g., MPI_REDUCE, MPI_ALLREDUCE, MPI_REDUCE_SCATTER, and MPI_SCAN) take a combination operation. This operation is of type MPI_Op in C and of type INTEGER in Fortran. The predefined operations are

MPI_MAX
return the maximum
MPI_MIN
return the minimum
MPI_SUM
return the sum
MPI_PROD
return the product
MPI_LAND
return the logical and
MPI_BAND
return the bitwise and
MPI_LOR
return the logical or
MPI_BOR
return the bitwise of
MPI_LXOR
return the logical exclusive or
MPI_BXOR
return the bitwise exclusive or
MPI_MINLOC
return the minimum and the location (actually, the value of the second element of the structure where the minimum of the first is found)
MPI_MAXLOC
return the maximum and the location
MPI_REPLACE
replace b with a
MPI_NO_OP
perform no operation

Notes on collective operations

The reduction functions (MPI_Op) do not return an error value. As a result, if the functions detect an error, all they can do is either call MPI_Abort or silently skip the problem. Thus, if you change the error handler from MPI_ERRORS_ARE_FATAL to something else, for example, MPI_ERRORS_RETURN, then no error may be indicated.

The reason for this is the performance problems in ensuring that all collective routines return the same error value.

Note that not all datatypes are valid for these functions. For example, MPI_COMPLEX is not valid for MPI_MAX and MPI_MIN. In addition, the MPI 1.1 standard did not include the C types MPI_CHAR and MPI_UNSIGNED_CHAR among the lists of arithmetic types for operations like MPI_SUM. However, since the C type char is an integer type (like short), it should have been included. The MPI Forum will probably include char and unsigned char as a clarification to MPI 1.1; until then, users are advised that MPI implementations may not accept MPI_CHAR and MPI_UNSIGNED_CHAR as valid datatypes for MPI_SUM, MPI_PROD, etc. MPICH does allow these datatypes.

Permanent key values

These are the same in C and Fortran

MPI_TAG_UB
Largest tag value
MPI_HOST
Rank of process that is host, if any
MPI_IO
Rank of process that can do I/O
MPI_WTIME_IS_GLOBAL
Has value 1 if MPI_WTIME is globally synchronized.
MPI_UNIVERSE_SIZE
Number of available processes. See the standard for a description of limitations on this value
MPI_LASTUSEDCODE
Last used MPI error code (check - code or class?)
MPI_APPNUM
Application number, starting from 0. See the standard for MPI_COMM_SPAWN_MULTIPLE and mpiexec for details

Null objects

MPI_COMM_NULL
Null communicator
MPI_OP_NULL
Null operation
MPI_GROUP_NULL
Null group
MPI_DATATYPE_NULL
Null datatype
MPI_REQUEST_NULL
Null request
MPI_ERRHANDLER_NULL
Null error handler
MPI_WIN_NULL
Null window handle
MPI_FILE_NULL
Null file handle
MPI_INFO_NULL
Null info handle
MPI_MESSAGE_NULL
Null message handle
MPI_ARGV_NULL
Empty ARGV value for spawn commands
MPI_ARGVS_NULL
Empty ARGV array for spawn-multiple command
MPI_T_ENUM_NULL
Null MPI_T enum
MPI_T_CVAR_HANDLE_NULL
Null MPI_T control variable handle
MPI_T_PVAR_HANDLE_NULL
Null MPI_T performance variable handle
MPI_T_PVAR_SESSION_NULL
Null MPI_T performance variable session handle

Predefined Constants

MPI_MAX_PROCESSOR_NAME
Maximum length of name returned by MPI_GET_PROCESSOR_NAME
MPI_MAX_ERROR_STRING
Maximum length of string return by MPI_ERROR_STRING
MPI_MAX_LIBRARY_VERSION_STRING
Maximum length of string returned by MPI_GET_LIBRARY_VERSION_STRING???
MPI_MAX_PORT_NAME
Maximum length of a port
MPI_MAX_OBJECT_NAME
Maximum length of an object (?)
MPI_MAX_INFO_KEY
Maximum length of an info key
MPI_MAX_INFO_VAL
Maximum length of an info value
MPI_UNDEFINED
Used by many routines to indicated undefined or unknown integer value
MPI_UNDEFINED_RANK
Unknown rank
MPI_KEYVAL_INVALID
Special keyval that may be used to detect uninitialized keyvals.
MPI_BSEND_OVERHEAD
Add this to the size of a MPI_BSEND buffer for each outstanding message
MPI_PROC_NULL
This rank may be used to send or receive from no-one.
MPI_ANY_SOURCE
In a receive, accept a message from anyone.
MPI_ANY_TAG
In a receive, accept a message with any tag value.
MPI_BOTTOM
May be used to indicate the bottom of the address space
MPI_IN_PLACE
Special location for buffer in some collective communication routines
MPI_VERSION
Numeric value of MPI version (e.g., 3)
MPI_SUBVERSION
Numeric value of MPI subversion (e.g., 1)

Topology types

MPI_CART
Cartesian grid
MPI_GRAPH
General graph
MPI_DIST_GRAPH
General distributed graph

Special values for distributed graph

MPI_UNWEIGHTED
Indicates that the edges are unweighted
MPI_WEIGHTS_EMPTY
Special address that indicates no array of weights information

File Modes

MPI_MODE_RDONLY
Read only
MPI_MODE_RDWR
Read and write
MPI_MODE_WRONLY
Write only
MPI_MODE_CREATE
Create the file if it does not exist
MPI_MODE_EXCL
It is an error if creating a file that already exists
MPI_MODE_DELETE_ON_CLOSE
Delete the file on close
MPI_MODE_UNIQUE_OPEN
The file will not be concurrently opened elsewhere
MPI_MODE_APPEND
The initial position of all file pointers is at the end of the file
MPI_MODE_SEQUENTIAL
File will only be accessed sequentially

File Displacement

MPI_DISPLACEMENT_CURRENT
Use with files opened with mode MPI_MODE_SEQUENTIAL in calls to MPI_FILE_SET_VIEW

File Positioning

MPI_SEEK_SET
Set the pointer to offset
MPI_SEEK_CUR
Set the pointer to the current position plus offset
MPI_SEEK_END
Set the pointer to the end of the file plus offset

Window attributes

MPI_WIN_BASE
window base address.
MPI_WIN_SIZE
window size, in bytes
MPI_WIN_DISP_UNIT
displacement unit associated with the window
MPI_WIN_CREATE_FLAVOR
how the window was created
MPI_WIN_MODEL
memory model for window

Window flavors

MPI_WIN_FLAVOR_CREATE
Window was created with MPI_WIN_CREATE.
MPI_WIN_FLAVOR_ALLOCATE
Window was created with MPI_WIN_ALLOCATE.
MPI_WIN_FLAVOR_DYNAMIC
Window was created with MPI_WIN_CREATE_DYNAMIC.
MPI_WIN_FLAVOR_SHARED
Window was created with MPI_WIN_ALLOCATE_SHARED.

Window Memory Model

MPI_WIN_SEPARATE
Separate public and private copies of window memory
MPI_WIN_UNIFIED
The public and private copies are identical (by which we mean that updates are eventually observed without additional RMA operations)

Window Lock Types

MPI_LOCK_EXCLUSIVE
Only one process at a time will execute accesses within the lock
MPI_LOCK_SHARED
Not exclusive; multiple processes may execute accesses within the lock

Window Assertions

See section 11.5 in MPI 3.1 for a detailed description of each of these assertion values.
MPI_MODE_NOCHECK
The matching calls to MPI_WIN_POST or MPI_WIN_START have already completed, or no process holds or will attempt to acquire, a conflicting lock.
MPI_MODE_NOSTORE
The local window has not been updated by stores since the last synchronization
MPI_MODE_NOPUT
The local window will not be updated by put or accumulate until the next synchronization
MPI_MODE_NOPRECEDE
The fence does not complete any locally issued RMA calls
MPI_MODE_NOSUCCEED
The fence does not start any locally issued RMA calls

Predefined Info Object

MPI_INFO_ENV
Contains the execution environment

MPI Status

The MPI_Status datatype is a structure in C. The three elements for use by programmers are
MPI_SOURCE
Who sent the message
MPI_TAG
What tag the message was sent with
MPI_ERROR
Any error return (only when the error returned by the routine has error class MPI_ERR_IN_STATUS)

MPI_STATUS_IGNORE
Ignore a single MPI_Status argument
MPI_STATUSES_IGNORE
Ignore an array of MPI_Status

Special value for error codes array

MPI_ERRCODES_IGNORE
Ignore an array of error codes

MPI_T Constants

MPI_T_VERBOSITY_USER_BASIC
Basic information of interest to users
MPI_T_VERBOSITY_USER_DETAIL
Detailed information of interest to users
MPI_T_VERBOSITY_USER_ALL
All remaining information of interest to users
MPI_T_VERBOSITY_TUNER_BASIC
Basic information required for tuning
MPI_T_VERBOSITY_TUNER_DETAIL
Detailed information required for tuning
MPI_T_VERBOSITY_TUNER_ALL
All remaining information required for tuning
MPI_T_VERBOSITY_MPIDEV_BASIC
Basic information for MPI implementors

MPI_T_VERBOSITY_MPIDEV_DETAIL
Detailed information for MPI implementors
MPI_T_VERBOSITY_MPIDEV_ALL
All remaining information for MPI implementors
MPI_T_BIND_NO_OBJECT
Applies globally to entire MPI process
MPI_T_BIND_MPI_COMM
MPI communicators
MPI_T_BIND_MPI_DATATYPE
MPI datatypes
MPI_T_BIND_MPI_ERRHANDLER
MPI error handlers
MPI_T_BIND_MPI_FILE
MPI file handles
MPI_T_BIND_MPI_GROUP
MPI groups
MPI_T_BIND_MPI_OP
MPI reduction operators
MPI_T_BIND_MPI_REQUEST
MPI requests
MPI_T_BIND_MPI_WIN
MPI windows for one-sided communication
MPI_T_BIND_MPI_MESSAGE
MPI message object
MPI_T_BIND_MPI_INFO
MPI info object
MPI_T_SCOPE_CONSTANT
read-only, value is constant
MPI_T_SCOPE_READONLY
read-only, cannot be written, but can change
MPI_T_SCOPE_LOCAL
may be writeable, writing is a local operation
MPI_T_SCOPE_GROUP
may be writeable, must be done to a group of processes, all processes in a group must be set to consistent values
MPI_T_SCOPE_GROUP_EQ
may be writeable, must be done to a group of processes, all processes in a group must be set to the same value
MPI_T_SCOPE_ALL
may be writeable, must be done to all processes, all connected processes must be set to consistent values
MPI_T_SCOPE_ALL_EQ
may be writeable, must be done to all processes, all connected processes must be set to the same value
MPI_T_PVAR_CLASS_STATE
set of discrete states (MPI_INT)
MPI_T_PVAR_CLASS_LEVEL
utilization level of a resource
MPI_T_PVAR_CLASS_SIZE
size of a resource
MPI_T_PVAR_CLASS_PERCENTAGE
percentage utilization of a resource
MPI_T_PVAR_CLASS_HIGHWATERMARK
high watermark of a resource
MPI_T_PVAR_CLASS_LOWWATERMARK
low watermark of a resource
MPI_T_PVAR_CLASS_COUNTER
number of occurrences of an event
MPI_T_PVAR_CLASS_AGGREGATE
aggregate value over an event (e.g., sum of all memory allocations)
MPI_T_PVAR_CLASS_TIMER
aggretate time spent executing event
MPI_T_PVAR_CLASS_GENERIC
used for any other time of performance variable

Thread levels

MPI_THREAD_SINGLE
Only one thread executes
MPI_THREAD_FUNNELED
Only the main thread makes MPI calls
MPI_THREAD_SERIALIZED
Only one thread at a time makes MPI calls
MPI_THREAD_MULTIPLE
Multiple threads may make MPI calls

Special MPI types and functions

MPI_Aint
C type that holds any valid address.
MPI_Count
C type that holds any valid count.
MPI_Offset
C type that holds any valid file offset.
MPI_Handler_function
C function for handling errors (see MPI_Errhandler_create) .
MPI_User_function
C function to combine values (see collective operations and MPI_Op_create)
MPI_Copy_function
Function to copy attributes (see MPI_Keyval_create)
MPI_Delete_function
Function to delete attributes (see MPI_Keyval_create)
MPI_ERRORS_ARE_FATAL
Error handler that forces exit on error
MPI_ERRORS_RETURN
Error handler that returns error codes (as value of MPI routine in C and through last argument in Fortran)
MPI_ERRORS_ABORT
Error handler that forces exit on error (only aborts local process if the error handler is invoked on a session)

MPI Attribute Default Functions

MPI_COMM_NULL_COPY_FN
Predefined attribute copy function for communicators
MPI_COMM_NULL_DELETE_FN
Predefined attribute delete function for communicators
MPI_COMM_DUP_FN
Predefined attribute duplicate function for communicators
MPI_WIN_NULL_COPY_FN
Predefined attribute copy function for windows
MPI_WIN_NULL_DELETE_FN
Predefined attribute delete function for windows
MPI_WIN_DUP_FN
Predefined attribute duplicate function for windows
MPI_TYPE_NULL_COPY_FN
Predefined attribute copy function for datatypes
MPI_TYPE_NULL_DELETE_FN
Predefined attribute delete function for datatypes
MPI_TYPE_DUP_FN
Predefined attribute duplicate function for datatypes

MPI-1 Attribute Default Functions

MPI_NULL_COPY_FN
Predefined copy function
MPI_NULL_DELETE_FN
Predefined delete function
MPI_DUP_FN
Predefined duplication function

MPI Error classes

MPI_SUCCESS
Successful return code
MPI_ERR_BUFFER
Invalid buffer pointer
MPI_ERR_COUNT
Invalid count argument
MPI_ERR_TYPE
Invalid datatype argument
MPI_ERR_TAG
Invalid tag argument
MPI_ERR_COMM
Invalid communicator
MPI_ERR_RANK
Invalid rank
MPI_ERR_ROOT
Invalid root
MPI_ERR_GROUP
Null group passed to function
MPI_ERR_OP
Invalid operation
MPI_ERR_TOPOLOGY
Invalid topology
MPI_ERR_DIMS
Illegal dimension argument
MPI_ERR_ARG
Invalid argument
MPI_ERR_UNKNOWN
Unknown error
MPI_ERR_TRUNCATE
Message truncated on receive
MPI_ERR_OTHER
Other error; use Error_string
MPI_ERR_INTERN
Internal error code
MPI_ERR_IN_STATUS
Look in status for error value
MPI_ERR_PENDING
Pending request
MPI_ERR_REQUEST
Invalid mpi_request handle
MPI_ERR_ACCESS
Permission denied
MPI_ERR_AMODE
Error related to the amode passed to MPI_FILE_OPEN
MPI_ERR_BAD_FILE
Invalid file name (e.g., path name too long)
MPI_ERR_CONVERSION
An error occurred in a user supplied data conversion function
MPI_ERR_DUP_DATAREP
Conversion functions could not be registered because a data representation identifier that was already defined was passed to MPI_REGISTER_DATAREP
MPI_ERR_FILE_EXISTS
File exists
MPI_ERR_FILE_IN_USE
File operation could not be completed, as the file is currently open by some process
MPI_ERR_FILE
Invalid file handle
MPI_ERR_IO
Other I/O error
MPI_ERR_NO_SPACE
Not enough space
MPI_ERR_NO_SUCH_FILE
File does not exist
MPI_ERR_READ_ONLY
Read-only file or file system
MPI_ERR_UNSUPPORTED_DATAREP
Unsupported datarep passed to MPI_FILE_SET_VIEW
MPI_ERR_INFO
Invalid info argument
MPI_ERR_INFO_KEY
Key longer than MPI_MAX_INFO_KEY
MPI_ERR_INFO_VALUE
Value longer than MPI_MAX_INFO_VAL
MPI_ERR_INFO_NOKEY
Invalid key passed to MPI_INFO_DELETE
MPI_ERR_NAME
Invalid service name passed to MPI_LOOKUP_NAME
MPI_ERR_NO_MEM
Alloc_mem could not allocate memory
MPI_ERR_NOT_SAME
Collective argument not identical on all processes, or collective routines called in a different order by different processes
MPI_ERR_PORT
Invalid port name passed to MPI_COMM_CONNECT
MPI_ERR_QUOTA
Quota exceeded
MPI_ERR_SERVICE
Invalid service name passed to MPI_UNPUBLISH_NAME
MPI_ERR_SPAWN
Error in spawning processes
MPI_ERR_UNSUPPORTED_OPERATION
Unsupported operation, such as seeking on a file which supports sequential access only
MPI_ERR_WIN
Invalid win argument
MPI_ERR_BASE
Invalid base passed to MPI_FREE_MEM
MPI_ERR_LOCKTYPE
Invalid locktype argument
MPI_ERR_KEYVAL
Erroneous attribute key
MPI_ERR_RMA_CONFLICT
Conflicting accesses to window
MPI_ERR_RMA_SYNC
Wrong synchronization of RMA calls
MPI_ERR_SIZE
Invalid size argument
MPI_ERR_DISP
Invalid disp argument
MPI_ERR_ASSERT
Invalid assert argument
MPI_ERR_RMA_RANGE
Target memory is not part of the window (in the case of a window created with MPI_WIN_CREATE_DYNAMIC, target memory is not attached)
MPI_ERR_RMA_ATTACH
Memory cannot be attached (e.g., because of resource exhaustion)
MPI_ERR_RMA_SHARED
Memory cannot be shared (e.g., some process in the group of the specified communicator cannot expose shared memory)
MPI_ERR_RMA_FLAVOR
Passed window has the wrong flavor for the called function
MPI_ERR_LASTCODE
Last error code -- always at end

Error codes for MPI_T

MPI_T_ERR_MEMORY
Out of memory
MPI_T_ERR_NOT_INITIALIZED
Interface not initialized
MPI_T_ERR_CANNOT_INIT
Interface not in the state to be initialized
MPI_T_ERR_INVALID_INDEX
The index is invalid or has been deleted
MPI_T_ERR_INVALID_HANDLE
The handle is invalid
MPI_T_ERR_OUT_OF_HANDLES
No more handles available
MPI_T_ERR_OUT_OF_SESSIONS
No more sessions available
MPI_T_ERR_INVALID_SESSION
Session argument is not valid
MPI_T_ERR_CVAR_SET_NOT_NOW
Cvar cannot be set at this moment
MPI_T_ERR_CVAR_SET_NEVER
Cvar cannot be set until end of execution
MPI_T_ERR_PVAR_NO_STARTSTOP
Pvar can't be started or stopped
MPI_T_ERR_PVAR_NO_WRITE
Pvar can't be written or reset
MPI_T_ERR_PVAR_NO_ATOMIC
Pvar can't be R/W atomically
MPI_T_ERR_INVALID_NAME
Name doesn't match
MPI_T_ERR_INVALID
Invalid use of the interface or bad parameter values(s)