--- name: "MPI_Publish_name.openmpi" section: "3" platform: "linux" package: "openmpi-doc" version: "5.0.7-1" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/MPI_Publish_name.openmpi" --- # MPI\_Publish\_name.openmpi(3) *MPI\_Publish\_name* — Publishes a service name associated with a port ## SYNTAX ### C Syntax ``` #include int MPI_Publish_name(const char *service_name, MPI_Info info, const char *port_name) ``` ### Fortran Syntax ``` USE MPI ! or the older form: INCLUDE 'mpif.h' MPI_PUBLISH_NAME(SERVICE_NAME, INFO, PORT_NAME, IERROR) CHARACTER*(*) SERVICE_NAME, PORT_NAME INTEGER INFO, IERROR ``` ### Fortran 2008 Syntax ``` USE mpi_f08 MPI_Publish_name(service_name, info, port_name, ierror) TYPE(MPI_Info), INTENT(IN) :: info CHARACTER(LEN=*), INTENT(IN) :: service_name, port_name INTEGER, OPTIONAL, INTENT(OUT) :: ierror ``` ## INPUT PARAMETERS - • **service\_name**: A service name (string). - • **info**: Options to the name service functions (handle). - • **port\_name**: A port name (string). ## OUTPUT PARAMETER - • **ierror**: Fortran only: Error status (integer). ## DESCRIPTION This routine publishes the pair (*service\_name, port\_name*) so that an application may retrieve *port\_name* by calling *MPI\_Lookup\_name* with *service\_name* as an argument. It is an error to publish the same *service\_name* twice, or to use a *port\_name* argument that was not previously opened by the calling process via a call to *MPI\_Open\_port*. ## INFO ARGUMENTS The following keys for *info* are recognized: ``` Key Type Description --- ---- ----------- ompi_global_scope bool If set to true, publish the name in the global scope. Publish in the local scope otherwise. See the NAME SCOPE section for more details. ompi_unique bool If set to true, return an error if the specified service_name already exists. Default to overwriting any pre-existing value. ``` *bool* info keys are actually strings but are evaluated as follows: if the string value is a number, it is converted to an integer and cast to a boolean (meaning that zero integers are false and non-zero values are true). If the string value is (case-insensitive) “yes” or “true”, the boolean is true. If the string value is (case-insensitive) “no” or “false”, the boolean is false. All other string values are unrecognized, and therefore false. If no info key is provided, the function will first check to see if a global server has been specified and is available. If so, then the publish function will default to global scope first, followed by local. Otherwise, the data will default to publish with local scope. ## NAME SCOPE Open MPI supports two name scopes: *global* and *local*. Local scope will place the specified service/port pair in a data store located on the mpirun of the calling process’ job. Thus, data published with local scope will only be accessible to processes in jobs spawned by that mpirun - e.g., processes in the calling process’ job, or in jobs spawned via *MPI\_Comm\_spawn*. Global scope places the specified service/port pair in a data store located on a central server that is accessible to all jobs running in the cluster or environment. Thus, data published with global scope can be accessed by multiple mpiruns and used for *MPI\_Comm\_connect* and *MPI\_Comm\_accept* between jobs. Note that global scope operations require both the presence of the central server and that the calling process be able to communicate to that server. *MPI\_Publish\_name* will return an error if global scope is specified and a global server is either not specified or cannot be found. Open MPI provides a server called *ompi-server* to support global scope operations. Please refer to its manual page for a more detailed description of data store/lookup operations. As an example of the impact of these scoping rules, consider the case where a job has been started with mpirun - call this job “job1”. A process in job1 creates and publishes a service/port pair using a local scope. Open MPI will store this data in the data store within mpirun. A process in job1 (perhaps the same as did the publish, or perhaps some other process in the job) subsequently calls *MPI\_Comm\_spawn* to start another job (call it “job2”) under this mpirun. Since the two jobs share a common mpirun, both jobs have access to local scope data. Hence, a process in job2 can perform an *MPI\_Lookup\_name* with a local scope to retrieve the information. However, assume another user starts a job using mpirun - call this job “job3”. Because the service/port data published by job1 specified local scope, processes in job3 cannot access that data. In contrast, if the data had been published using global scope, then any process in job3 could access the data, provided that mpirun was given knowledge of how to contact the central server and the process could establish communication with it. ## ERRORS Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument. Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI\_COMM\_SELF and will call the associated MPI error handler. When MPI\_COMM\_SELF is not initialized (i.e., before *MPI\_Init*/*MPI\_Init\_thread*, after *MPI\_Finalize*, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling *MPI\_Comm\_set\_errhandler* on MPI\_COMM\_SELF when using the World model, or the mpi\_initial\_errhandler CLI argument to mpiexec or info key to *MPI\_Comm\_spawn*/*MPI\_Comm\_spawn\_multiple*. If no other appropriate error handler has been set, then the MPI\_ERRORS\_RETURN error handler is called for MPI I/O functions and the MPI\_ERRORS\_ABORT error handler is called for all other MPI functions. Open MPI includes three predefined error handlers that can be used: - • **MPI\_ERRORS\_ARE\_FATAL** Causes the program to abort all connected MPI processes. - • **MPI\_ERRORS\_ABORT** An error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if *MPI\_Abort* was called on that communicator. If called on a window or file, acts as if *MPI\_Abort* was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process. - • **MPI\_ERRORS\_RETURN** Returns an error code to the application. MPI applications can also implement their own error handlers by calling: - • *MPI\_Comm\_create\_errhandler* then *MPI\_Comm\_set\_errhandler* - • *MPI\_File\_create\_errhandler* then *MPI\_File\_set\_errhandler* - • *MPI\_Session\_create\_errhandler* then *MPI\_Session\_set\_errhandler* or at *MPI\_Session\_init* - • *MPI\_Win\_create\_errhandler* then *MPI\_Win\_set\_errhandler* Note that MPI does not guarantee that an MPI program can continue past an error. See the *MPI man page* for a full list of *MPI error codes*. See the Error Handling section of the MPI-3.1 standard for more information. **SEE ALSO:** - • *MPI\_Lookup\_name* - • *MPI\_Open\_port* ## COPYRIGHT 2003-2025, The Open MPI Community