Initialize the mpi_t execution environment
int MPI_T_init_thread(int required, int *provided)
- desired level of thread support (integer)
- provided level of thread support (integer)
- Only one thread will execute.
- The process may be multi-threaded, but only the main thread will make MPI_T calls (all MPI_T calls are funneled to the main thread).
- The process may be multi-threaded, and multiple threads may make MPI_T calls, but only one at a time: MPI_T calls are not made concurrently from two distinct threads (all MPI_T calls are serialized).
- Multiple threads may call MPI_T, with no restrictions.
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.
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 guarentee that an MPI program can continue past an error; however, MPI implementations will attempt to continue whenever possible.
- No error; MPI routine completed successfully.