MPI_Query_thread - Returns the current level of thread support
int MPI_Query_thread(int *provided)
INTEGER PROVIDED, IERROR
provided C/Fortran only: Level of thread support (integer).
IERROR Fortran only: Error status (integer).
This routine returns in provided the current level of thread support.
If MPI was initialized by a call to MPI_Init_thread, provided will have
the same value as was returned by that function.
The possible values of provided are as follows:
MPI_THREAD_SINGLE Only one thread may execute.
MPI_THREAD_FUNNELED If the process is multithreaded, only the
thread that called MPI_Init[_thread] may make
MPI_THREAD_SERIALIZED If the process is multithreaded, only one
thread may make MPI library calls at one time.
MPI_THREAD_MULTIPLE If the process is multithreaded, multiple
threads may call MPI at once with no
In Open MPI, provided is always MPI_THREAD_SINGLE, unless the program
has been linked with the multithreaded library, in which case provided
Almost all MPI routines return an error value; C routines as the value
of the function and Fortran routines in the last argument. C++
functions do not return errors. If the default error handler is set to
MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
will be used to throw an MPI:Exception object.
Before the error value is returned, the current MPI error handler is
called. By default, this error handler aborts the MPI job, except for
I/O function errors. The error handler may be changed with
MPI_Comm_set_errhandler; 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.
See the MPI man page for a full list of MPI error codes.