openmpi/ompi/mpi/man/man5/Open-MPI.5.md

# NAME

Open MPI - General information

# OPEN MPI

Open MPI is an open source implementation of MPI (message-passing
interface), the industry-standard specification for writing
message-passing programs. Message passing is a programming model that
gives the programmer explicit control over interprocess communication.

The MPI specification was developed by the MPI Forum, a group of
software developers, computer vendors, academics, and computer-science
researchers whose goal was to develop a standard for writing
message-passing programs that would be efficient, flexible, and
portable.

The outcome, known as the MPI Standard, was first published in 1993; its
most recent version (MPI-2) was published in July 1997. Open MPI 1.2
includes all MPI 1.2-compliant and MPI 2-compliant routines.

For more information about Open MPI, see
[https://www.open-mpi.org](https://www.open-mpi.org).

The MPI standards are available at
[https://www.mpi-forum.org](https://www.mpi-forum.org).

# MAN PAGE SYNTAX

Man pages for Open MPI and Open MPI I/O routines are named according to
C syntax, that is, they begin with the prefix `MPI_`, all in
uppercase, and the first letter following the `MPI_` prefix is also
uppercase. The rest of the letters in the routine are all lowercase, for
example, `MPI_Comm_get_attr`.

# ENVIRONMENT

To fine-tune your Open MPI environment, you can either use arguments
to the `mpirun` or `mpiexec` commands, or you can use MCA parameters.

For more information on arguments, see the `mpirun`(1) man page.

For a complete listing of MCA parameters and their descriptions, issue
the command `ompi_info --all`. This information also appears in the
FAQ on the Open MPI web site at
[https://www.open-mpi.org/faq/?category=tuning#mca-params](https://www.open-mpi.org/faq/?category=tuning#mca-params).

# ERRORS

All MPI routines (except `MPI_Wtime` and `MPI_Wtick`) return an error
value; C routines as the value of the function and Fortran routines in
the last argument. Before the value is returned, the current MPI error
handler is called. By default, this error handler aborts the MPI job.
The error handler may be changed with `MPI_Comm_set_errhandler`; the
predefined error handler `MPI_ERRORS_RETURN` may be used to cause error
values to be returned. Note that MPI does not guarantee that an MPI
program can continue past an error.

For more information on Open MPI error codes, see `mpi.h` in the
`include` directory.

Standard error return classes for Open MPI:

| Error name | Error value | Description |
|---|---|---|
| MPI_SUCCESS | 0 | Successful return code. |
| MPI_ERR_BUFFER | 1 | Invalid buffer pointer. |
| MPI_ERR_COUNT | 2 | Invalid count argument. |
| MPI_ERR_TYPE | 3 | Invalid datatype argument. |
| MPI_ERR_TAG | 4 | Invalid tag argument. |
| MPI_ERR_COMM | 5 | Invalid communicator. |
| MPI_ERR_RANK | 6 | Invalid rank. |
| MPI_ERR_REQUEST | 7 | Invalid MPI_Request handle. |
| MPI_ERR_ROOT | 8 | Invalid root. |
| MPI_ERR_GROUP | 9 | Null group passed to function. |
| MPI_ERR_OP | 10 | Invalid operation. |
| MPI_ERR_TOPOLOGY | 11 | Invalid topology. |
| MPI_ERR_DIMS | 12 | Illegal dimension argument. |
| MPI_ERR_ARG | 13 | Invalid argument. |
| MPI_ERR_UNKNOWN | 14 | Unknown error. |
| MPI_ERR_TRUNCATE | 15 | Message truncated on receive. |
| MPI_ERR_OTHER | 16 | Other error; use Error_string. |
| MPI_ERR_INTERN | 17 | Internal error code. |
| MPI_ERR_IN_STATUS | 18 | Look in status for error value. |
| MPI_ERR_PENDING | 19 | Pending request. |
| MPI_ERR_ACCESS | 20 | Permission denied. |
| MPI_ERR_AMODE | 21 | Unsupported amode passed to open. |
| MPI_ERR_ASSERT | 22 | Invalid assert. |
| MPI_ERR_BAD_FILE | 23 | Invalid file name (for example, path name too long). |
| MPI_ERR_BASE | 24 | Invalid base. |
| MPI_ERR_CONVERSION | 25 | An error occurred in a user-supplied data-conversion function. |
| MPI_ERR_DISP | 26 | Invalid displacement. |
| MPI_ERR_DUP_DATAREP | 27 | 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 | 28 | File exists. |
| MPI_ERR_FILE_IN_USE | 29 | File operation could not be completed, as the file is currently open by some process. |
| MPI_ERR_FILE | 30 | Invalid file handle. |
| MPI_ERR_INFO_KEY | 31 | Illegal info key. |
| MPI_ERR_INFO_NOKEY | 32 | No such key. |
| MPI_ERR_INFO_VALUE | 33 | Illegal info value. |
| MPI_ERR_INFO | 34 | Invalid info object. |
| MPI_ERR_IO | 35 | I/O error. |
| MPI_ERR_KEYVAL | 36 | Illegal key value. |
| MPI_ERR_LOCKTYPE | 37 | Invalid locktype. |
| MPI_ERR_NAME | 38 | Name not found. |
| MPI_ERR_NO_MEM | 39 | Memory exhausted. |
| MPI_ERR_NOT_SAME | 40 | Collective argument not identical on all processes, or collective routines called in a different order by different processes. |
| MPI_ERR_NO_SPACE | 41 | Not enough space. |
| MPI_ERR_NO_SUCH_FILE | 42 | File (or directory) does not exist. |
| MPI_ERR_PORT | 43 | Invalid port. |
| MPI_ERR_PROC_ABORTED | 74 | Operation failed because a remote peer has aborted. |
| MPI_ERR_QUOTA | 44 | Quota exceeded. |
| MPI_ERR_READ_ONLY | 45 | Read-only file system. |
| MPI_ERR_RMA_CONFLICT | 46 | Conflicting accesses to window. |
| MPI_ERR_RMA_SYNC | 47 | Erroneous RMA synchronization. |
| MPI_ERR_SERVICE | 48 | Invalid publish/unpublish. |
| MPI_ERR_SIZE | 49 | Invalid size. |
| MPI_ERR_SPAWN | 50 | Error spawning. |
| MPI_ERR_UNSUPPORTED_DATAREP | 51 | Unsupported datarep passed to MPI_File_set_view. |
| MPI_ERR_UNSUPPORTED_OPERATION | 52 | Unsupported operation, such as seeking on a file that supports only sequential access. |
| MPI_ERR_WIN | 53 | Invalid window. |
| MPI_T_ERR_MEMORY | 54 | Out of memory. |
| MPI_T_ERR_NOT_INITIALIZED | 55 | Interface not initialized. |
| MPI_T_ERR_CANNOT_INIT | 56 | Interface not in the state to be initialized. |
| MPI_T_ERR_INVALID_INDEX | 57 | The enumeration index is invalid. |
| MPI_T_ERR_INVALID_ITEM| 58 | The item index queried is out of range. |
| MPI_T_ERR_INVALID_HANDLE | 59 | The handle is invalid. |
| MPI_T_ERR_OUT_OF_HANDLES | 60 | No more handles available. |
| MPI_T_ERR_OUT_OF_SESSIONS | 61 | No more sessions available. |
| MPI_T_ERR_INVALID_SESSION | 62 | Session argument is not a valid session. |
| MPI_T_ERR_CVAR_SET_NOT_NOW | 63 |Variable cannot be set at this moment. |
| MPI_T_ERR_CVAR_SET_NEVER | 64 | Variable cannot be set until end of execution. |
| MPI_T_ERR_PVAR_NO_STARTSTOP | 65 | Variable cannot be started or stopped. |
| MPI_T_ERR_PVAR_NO_WRITE | 66 | Variable cannot be written or reset. |
| MPI_T_ERR_PVAR_NO_ATOMIC | 67 | Variable cannot be read and written atomically. |
| MPI_ERR_RMA_RANGE | 68 | 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 | 69 | Memory cannot be attached (e.g., because of resource exhaustion). |
| MPI_ERR_RMA_FLAVOR | 70 | Passed window has the wrong flavor for the called function. |
| MPI_ERR_RMA_SHARED | 71 | Memory cannot be shared (e.g., some process in the group of the specified communicator cannot expose shared memory). |
| MPI_T_ERR_INVALID | 72 | Invalid use of the interface or bad parameter values(s). |
| MPI_T_ERR_INVALID_NAME | 73 | The variable or category name is invalid. |
| MPI_ERR_LASTCODE | 93 | Last error code. |

# SEE ALSO

MPI_T(5)