18.2.13. MPI_Alloc_mem
MPI_Alloc_mem - Allocates a specified memory segment.
18.2.13.1. SYNTAX
18.2.13.1.1. C Syntax
#include <mpi.h>
int MPI_Alloc_mem(MPI_Aint size, MPI_Info info, void *baseptr)
18.2.13.1.2. 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
18.2.13.1.3. 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
18.2.13.2. INPUT PARAMETERS
size
: Size of memory segment in bytes (nonnegative integer).info
: Info argument (handle).
18.2.13.3. OUTPUT PARAMETERS
baseptr
: Pointer to beginning of memory segment allocated.IERROR
: Fortran only: Error status (integer).
18.2.13.4. DESCRIPTION
MPI_Alloc_mem allocates size bytes of memory. The starting address of this memory is returned in the variable baseptr.
18.2.13.5. C NOTES
The parameter baseptr is of type void * to allow passing any pointer object for this parameter. The provided argument should be a pointer to a pointer of arbitrary type (e.g., void **).
18.2.13.6. 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_Alloc_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 Fortran User’s Guide and are supported by many Fortran compilers. For example,
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)
18.2.13.7. ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.
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