MPI_Improbe(3) Open MPI MPI_Improbe(3)
NAME
MPI_Improbe - Non-blocking matched probe for a message.
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Improbe(int source, int tag, MPI_Comm comm,
int *flag, MPI_Message *message, MPI_Status *status)
Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_IMPROBE(SOURCE, TAG, COMM, FLAG, MESSAGE, STATUS, IERROR)
LOGICAL FLAG
INTEGER SOURCE, TAG, COMM, MESSAGE
INTEGER STATUS(MPI_STATUS_SIZE), IERROR
Fortran 2008 Syntax
USE mpi_f08
MPI_Improbe(source, tag, comm, flag, message, status, ierror)
INTEGER, INTENT(IN) :: source, tag
TYPE(MPI_Comm), INTENT(IN) :: comm
INTEGER, INTENT(OUT) :: flag
TYPE(MPI_Message), INTENT(OUT) :: message
TYPE(MPI_Status) :: status
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
C++ Syntax
There is no C++ binding for this function.
INPUT PARAMETERS
source Source rank or MPI_ANY_SOURCE (integer).
tag Tag value or MPI_ANY_TAG (integer).
comm Communicator (handle).
OUTPUT PARAMETERS
flag Flag (logical).
message Message (handle).
status Status object (status).
IERROR Fortran only: Error status (integer).
DESCRIPTION
Like MPI_Probe and MPI_Iprobe, the MPI_Mprobe and MPI_Improbe opera-
tions allow incoming messages to be queried without actually receiving
them, except that MPI_Mprobe and MPI_Improbe provide a mechanism to re-
ceive the specific message that was matched regardless of other inter-
vening probe or receive operations. This gives the application an op-
portunity to decide how to receive the message, based on the informa-
tion returned by the probe. In particular, the application may allo-
cate memory for the receive buffer according to the length of the
probed message.
A matching probe with MPI_PROC_NULL as source returns flag = true, mes-
sage = MPI_MESSAGE_NO_PROC, and the status object returns source =
MPI_PROC_NULL, tag = MPI_ANY_TAG, and count = 0.
MPI_Iprobe returns a true value in flag if a message has been matched
and can be received by passing the message handle to the MPI_Mrecv or
MPI_Imrecv functions, provided the source was not MPI_PROC_NULL.
NOTE
This is an MPI-3 function and has no C++ binding.
ERRORS
Almost all MPI routines return an error value; C routines as the value
of the function and Fortran routines in the last argument. C++ func-
tions do not return errors.
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 ALSO
MPI_Mprobe
MPI_Probe
MPI_Iprobe
MPI_Mrecv
MPI_Imrecv
MPI_Cancel
4.1.2 Nov 24, 2021 MPI_Improbe(3)
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