MPI_Alloc_mem(3) Open MPI MPI_Alloc_mem(3)
NAME
MPI_Alloc_mem - Allocates a specified memory segment.
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Alloc_mem(MPI_Aint size, MPI_Info info, void *baseptr)
Fortran Syntax (see FORTRAN NOTES)
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_ALLOC_MEM(SIZE, INFO, BASEPTR, IERROR)
INTEGER INFO, IERROR
INTEGER(KIND=MPI_ADDRESS_KIND) SIZE, BASEPTR
Fortran 2008 Syntax
USE mpi_f08
MPI_Alloc_mem(size, info, baseptr, ierror)
USE, INTRINSIC :: ISO_C_BINDING, ONLY
INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: size
TYPE(MPI_Info), INTENT(IN) :: info
TYPE(C_PTR), INTENT(OUT) :: baseptr
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
C++ Syntax
#include <mpi.h>
void* MPI::Alloc_mem(MPI::Aint size, const MPI::Info& info)
INPUT PARAMETERS
size Size of memory segment in bytes (nonnegative integer).
info Info argument (handle).
OUTPUT PARAMETERS
baseptr Pointer to beginning of memory segment allocated.
IERROR Fortran only: Error status (integer).
DESCRIPTION
MPI_Alloc_mem allocates size bytes of memory. The starting address of
this memory is returned in the variable base.
FORTRAN NOTES
There is no portable FORTRAN 77 syntax for using MPI_Alloc_mem. There
is no portable Fortran syntax for using pointers returned from MPI_Al-
loc_mem. However, MPI_Alloc_mem can be used with Sun Fortran compilers.
From FORTRAN 77, you can use the following non-standard declarations
for the SIZE and BASEPTR arguments:
INCLUDE "mpif.h"
INTEGER*MPI_ADDRESS_KIND SIZE, BASEPTR
From either FORTRAN 77 or Fortran 90, you can use "Cray pointers" for
the BASEPTR argument. Cray pointers are described further in the For-
tran User's Guide and are supported by many Fortran compilers. For ex-
ample,
INCLUDE "mpif.h"
REAL*4 A(100,100)
POINTER (BASEPTR, A)
INTEGER*MPI_ADDRESS_KIND SIZE
SIZE = 4 * 100 * 100
CALL MPI_ALLOC_MEM(SIZE,MPI_INFO_NULL,BASEPTR,IERR)
! use A
CALL MPI_FREE_MEM(A, IERR)
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. 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 ALSO
MPI_Free_mem
4.1.2 Nov 24, 2021 MPI_Alloc_mem(3)
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