oracular (3) MPI_Query_thread.3.gz

NAME

       MPI_Query_thread -  Return the level of thread support provided by the MPI library

SYNOPSIS

       int MPI_Query_thread(int *provided)

OUTPUT PARAMETERS

       provided
              - provided level of thread support (integer)

NOTES

       The valid values for the level of thread support are:
       MPI_THREAD_SINGLE
              - Only one thread will execute.
       MPI_THREAD_FUNNELED
              -  The  process may be multi-threaded, but only the main thread will make MPI calls (all MPI calls
              are funneled to the main thread).
       MPI_THREAD_SERIALIZED
              - The process may be multi-threaded, and multiple threads may make MPI calls, but only  one  at  a
              time:  MPI  calls  are  not  made  concurrently  from  two  distinct  threads  (all  MPI calls are
              serialized).
       MPI_THREAD_MULTIPLE
              - Multiple threads may call MPI, with no restrictions.

              If MPI_Init was called instead of MPI_Init_thread , the level of thread support is defined by  the
              implementation.   This  routine  allows you to find out the provided level.  It is also useful for
              library routines that discover that MPI has already been initialized and wish  to  determine  what
              level of thread support is available.

THREAD AND INTERRUPT SAFETY

       This routine is thread-safe.  This means that this routine may be safely used by multiple threads without
       the need for any user-provided thread locks.  However, the routine is  not  interrupt  safe.   Typically,
       this  is  due to the use of memory allocation routines such as malloc or other non-MPICH runtime routines
       that are themselves not interrupt-safe.

NOTES FOR FORTRAN

       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the
       end of the argument list.  ierr is an integer and has the same meaning as the return value of the routine
       in C.  In Fortran, MPI routines are subroutines, and are invoked with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

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   (for   communicators),   MPI_File_set_errhandler   (for   files),   and
       MPI_Win_set_errhandler (for RMA windows).  The MPI-1 routine MPI_Errhandler_set may be used but  its  use
       is  deprecated.   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; however,  MPI
       implementations will attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_ARG
              -  Invalid  argument.   Some  argument  is invalid and is not identified by a specific error class
              (e.g., MPI_ERR_RANK ).
       MPI_ERR_OTHER
              - Other error; use MPI_Error_string to get more information about this error code.

                                                    2/9/2024                                 MPI_Query_thread(3)