MPI\_T\_PVAR\_STOP(3) Open MPI MPI\_T\_PVAR\_STOP(3) MPI\_T\_pvar\_start <#mpi-t-pvar-start>, MPI\_T\_pvar\_stop - Start/stop a performance variable # [SYNTAX](#SYNTAX) ## [C Syntax](#C_Syntax) ``` #include int MPI_T_pvar_start(MPI_T_pvar_session session, MPI_T_pvar_handle handle) int MPI_T_pvar_stop(MPI_T_pvar_session session, MPI_T_pvar_handle handle) ``` # [INPUT PARAMETERS](#INPUT_PARAMETERS) - **session**: Performance experiment session. - **handle**: Performance variable handle. # [DESCRIPTION](#DESCRIPTION) MPI\_T\_pvar\_start <#mpi-t-pvar-start> starts the performance variable with the handle specified in *handle*. The special value MPI\_T\_PVAR\_ALL\_HANDLES can be passed in *handle* to start all non-continuous handles in the session specified in *session*. MPI\_T\_pvar\_stop stops the performance variable with the handle specified in *handle*. The special value MPI\_T\_PVAR\_ALL\_HANDLES can be passed in *handle* to stop all non-continuous handles in the session specified in *session*. Continuous performance variables can neither be started nor stopped. # [ERRORS](#ERRORS) MPI\_T\_pvar\_start <#mpi-t-pvar-start> and MPI\_T\_pvar\_stop() will fail if: - **MPI\_T\_ERR\_NOT\_INITIALIZED**: The MPI Tools interface not initialized - **MPI\_T\_ERR\_INVALID\_SESSION**: Session parameter is not a valid session - **MPI\_T\_ERR\_INVALID\_HANDLE**: Invalid handle or handle not associated with the session - **MPI\_T\_ERR\_PVAR\_NO\_STARTSTOP**: The variable cannot be started or stopped **See also:** • MPI\_T\_pvar\_get\_info <#mpi-t-pvar-get-info> # [Copyright](#Copyright) 2003-2026, The Open MPI Community September 16, 2026 --- Document: MPI_T_pvar_stop(3) from openmpi-cuda-12.8 5.0.11-r1 (Chainguard OS) Source: https://github.com/open-mpi/ompi