Man page - mpi_t_init_thread.openmpi(3)

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Manual

MPI_T_INIT_THREAD

SYNTAX
C Syntax
INPUT PARAMETERS
OUTPUT PARAMETERS
DESCRIPTION
NOTES
ERRORS
COPYRIGHT

MPI_T_init_thread — Initializes the MPI Tool information 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_T

•

MPI_Init

•

MPI_Init_thread

COPYRIGHT

2003-2025, The Open MPI Community