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_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)

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++ functions 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

4.1.6                                             Sep 30, 2023                                  MPI_Alloc_mem(3)