# 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 minumum
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 publich 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 occurances 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 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_ITEM
  Item index queried is out of range
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 can't be set at this moment
MPI_T_ERR_CVAR_SET_NEVER
  Cvar can't 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)