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MPI_Win_lock_all(3) MPI MPI_Win_lock_all(3)

NAME

MPI_Win_lock_all - Begin an RMA access epoch at all processes on the given window

SYNOPSIS



int MPI_Win_lock_all(int assert, MPI_Win win)










INPUT PARAMETERS



  

  
- program assertion (integer)

  

  
- window object (handle)
    

  








NOTES


This call is not collective.


The assert argument is used to indicate special conditions
    for the fence that an implementation may use to optimize the
    MPI_Win_lock_all operation. The value zero is always correct. Other
    assertion values may be or'ed together. Assertions that are valid for
    MPI_Win_lock_all are:





  
MPI_MODE_NOCHECK

  

    
- No other process holds, or will attempt to acquire a
        conflicting lock, while the caller holds the window lock. This is useful
        when mutual exclusion is achieved by other means, but the coherence
        operations that may be attached to the lock and unlock calls are still
        required.

    
There may be additional overheads associated with using
        MPI_Win_lock and MPI_Win_lock_all concurrently on the same
        window. These overheads could be avoided by specifying the assertion
        MPI_MODE_NOCHECK when possible

    

  








THREAD AND INTERRUPT SAFETY


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.








NOTES FOR FORTRAN


All MPI routines in Fortran (except for MPI_WTIME and
    MPI_WTICK ) have an additional argument ierr at the end of the
    argument list. ierr is an integer and has the same meaning as the
    return value of the routine in C. In Fortran, MPI routines are subroutines,
    and are invoked with the call statement.


All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are
    of type INTEGER in Fortran.








ERRORS


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 guarantee that an MPI
    program can continue past an error; however, MPI implementations will
    attempt to continue whenever possible.





  

  
- No error; MPI routine completed successfully.

  

  
- Invalid MPI window object

  

  
- Other error; use MPI_Error_string to get more information about
      this error code.
    

  








SEE ALSO


MPI_Win_unlock_all







  

    2/9/2024