MPI_Thread(3)MPI_Thread(3)NAME
MPI_Thread - Returns MPI thread information
SYNOPSIS
C:
#include <mpi.h>
int MPI_Init_thread(int *argc, char ***argv, int required,
int *provided);
int MPI_Query_thread(int *provided);
int MPI_Is_thread_main(int *flag);
Fortran:
INCLUDE "mpif.h" (or USE MPI)
INTEGER required, provided, ierror
CALL MPI_INIT_THREAD(required, provided, ierror)
INTEGER provided
CALL MPI_QUERY_THREAD(provided)
LOGICAL flag
INTEGER ierror
CALL MPI_IS_THREAD_MAIN(flag, ierror)
DESCRIPTION
The following MPI_Thread routines return MPI thread information:
MPI_Init_thread The MPI_Init_thread routine initializes the MPI
execution environment in the same way that a call to
MPI_INIT would. In addition, it initializes the
thread environment.
This routine accepts the following parameters:
* argc, which specifies a pointer to the
number of arguments.
* argv, which specifies a pointer to the
argument vector.
* required, which specifies the desired level
of thread support. The following possible
values are listed in increasing order of
thread support:
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MPI_Thread(3)MPI_Thread(3)
MPI_THREAD_SINGLE: Only one thread will
execute.
MPI_THREAD_FUNNELED: The process can be
multithreaded, but only the main thread
will make MPI calls.
MPI_THREAD_SERIALIZED: The process can be
multithreaded, and multiple threads can
make MPI calls, but only one at a time.
MPI calls are not made concurrently from
two distinct threads.
MPI_THREAD_MULTIPLE: Multiple threads can
call MPI.
* provided, which specifies the actual level
of thread support provided by MPI. It can
have one of the four values in the previous
option list.
MPI_Query_thread The MPI_Query_thread routine returns, in provided,
the current level of thread support.
MPI_Is_thread_main The MPI_Is_thread_main routine can be called by a
thread to find out whether it is the main thread. The
main thread is the thread that called MPI_Init or
MPI_Init_thread. The answer is returned in flag.
NOTES
MPI statistics (see the MPI_SGI_stat man page) are not thread safe.
SEE ALSOMPI_SGI_stat(3)
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