MPI_T_PVAR_READRESET(3)				     Open MPI				   MPI_T_PVAR_READRESET(3)

MPI_T_pvar_readreset — Atomically read and reset the value of a performance variable

SYNTAX
   C Syntax
	  #include <mpi.h>

	  int MPI_T_pvar_readreset(MPI_T_pvar_session session, MPI_T_pvar_handle handle, const void *buf)

INPUT PARAMETERS
       • session: Performance experiment session.

       • handle: Performance variable handle.

       • buf: Initial address of storage location for variable value.

DESCRIPTION
       MPI_T_pvar_readreset  atomically queries and resets the value of a performance variable bound to the handle
       specified by handle in the session specified by session. The result is stored in the buffer pointed  to	by
       buf. This function can only be used with performance variables that are atomic and not readonly. The caller
       must  ensure  that the buffer pointed to by buf is large enough to hold the entire value of the performance
       variable.

ERRORS
       MPI_T_pvar_readreset will fail if:

       • MPI_T_ERR_NOT_INITIALIZED: The MPI Tools interface not initialized

       • MPI_T_ERR_INVALID_HANDLE: The handle is invalid or not associated with the session

       • MPI_T_ERR_INVALID_SESSION: Session argument is not a valid session

       • MPI_T_ERR_PVAR_NO_ATOMIC: Variable cannot be read and written atomically

       • MPI_T_ERR_PVAR_NO_WRITE: Variable cannot be reset

       See also:

	  • MPI_T_pvar_handle_alloc <#mpi-t-pvar-handle-alloc>

	  • MPI_T_pvar_get_info <#mpi-t-pvar-get-info>

	  • MPI_T_pvar_session_create <#mpi-t-pvar-session-create>

	  • MPI_T_pvar_read <#mpi-t-pvar-read>

	  • MPI_T_pvar_reset <#mpi-t-pvar-reset>

Copyright
       2003-2026, The Open MPI Community

						   Mar 05, 2026				   MPI_T_PVAR_READRESET(3)
