noble (3) MPI_T_init_thread.openmpi.3.gz

NAME

       MPI_T_init_thread - Initializes the MPI Tool imformation interface

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_T_init_thread(int required, int *provided)

INPUT PARAMETERS

       required  Desired level of thread support (integer).

OUTPUT PARAMETERS

       provided  Available level of thread support (integer).

DESCRIPTION

       MPI_T_init_thread()  initializes  the  MPI  tool  information  interface. Calls to MPI tool functions are
       allowed at any point in execution (including before MPI_Init()  and  after  MPI_Finalize())  as  long  as
       MPI_T_init_thread()  has  been  called  at  least  once and the number of calls to MPI_T_init_thread() is
       greater than the number of calls to MPI_T_finalize(). If at any point in execution the number of calls to
       MPI_T_finalize()  equals the number of calls to MPI_T_init_thread() the MPI tool interface will no longer
       be available until another call to MPI_T_init_thread().

       MPI_T_init_thread, like MPI_Init_thread, has a provision to request a certain level of thread support  in
       required:

       MPI_THREAD_SINGLE       Only one thread will execute.

       MPI_THREAD_FUNNELED     If the process is multithreaded, only the thread that called MPI_Init_thread will
                               make MPI calls.

       MPI_THREAD_SERIALIZED   If the process is multithreaded, only one thread will make MPI library  calls  at
                               one time.

       MPI_THREAD_MULTIPLE     If  the  process  is multithreaded, multiple threads may call MPI at once with no
                               restrictions.

       The level of thread support available to the program is set in  provided.  In  Open  MPI,  the  value  is
       dependent on how the library was configured and built. Note that there is no guarantee that provided will
       be greater than or equal to required.

NOTES

       It is the caller's responsibility to check the value of provided,  as  it  may  be  less  than  what  was
       requested in required.

ERRORS

       MPI_T_init_thread() will fail if:

       [MPI_T_ERR_MEMORY]
                 Out of memory

       [MPI_T_ERR_CANNOT_INIT]
                 Interface not in the state to be initialized

SEE ALSO

       MPI_Init_thread
       MPI_T_finalize