MPI_Request_free(3) MPI MPI_Request_free(3)NAMEMPI_Request_free - Frees a communication request object
SYNOPSIS
int MPI_Request_free(MPI_Request *request)
INPUT PARAMETERS
request
- communication request (handle)
NOTES
This routine is normally used to free inactive persistent requests cre‐
ated with either MPI_Recv_init or MPI_Send_init and friends. It is
also permissible to free an active request. However, once freed, the
request can no longer be used in a wait or test routine (e.g., MPI_Wait
) to determine completion.
This routine may also be used to free a non-persistent requests such as
those created with MPI_Irecv or MPI_Isend and friends. Like active
persistent requests, once freed, the request can no longer be used with
test/wait routines to determine completion.
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 com‐
municators), 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 prede‐
fined 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.
MPI_SUCCESS
- No error; MPI routine completed successfully.
MPI_ERR_REQUEST
- Invalid MPI_Request . Either null or, in the case of a
MPI_Start or MPI_Startall , not a persistent request.
MPI_ERR_ARG
- Invalid argument. Some argument is invalid and is not identi‐
fied by a specific error class (e.g., MPI_ERR_RANK ).
SEE ALSO
also: MPI_Isend, MPI_Irecv, MPI_Issend, MPI_Ibsend, MPI_Irsend,
MPI_Recv_init, MPI_Send_init, MPI_Ssend_init, MPI_Rsend_init, MPI_Wait,
MPI_Test, MPI_Waitall, MPI_Waitany, MPI_Waitsome, MPI_Testall, MPI_Tes‐
tany, MPI_Testsome
LOCATION
src/mpi/pt2pt/request_free.c
8/22/2013 MPI_Request_free(3)
