使用定义的输入过程从 Fortran 中的二进制文件中读取错误值
Reading bad values from binary file in Fortran with a defined input procedure
我正在尝试编写一个简单的代码,它获取一些具有相同父抽象的对象 class,将它们存储到一个二进制文件中并读回它们。
我的代码如下所示:
module m
implicit none
type :: container
class(a), allocatable :: item
end type container
type, abstract :: a
character(20), public :: obj_type
integer, public :: num
contains
procedure :: write_impl => write_a
procedure :: read_impl => read_a
generic :: write(unformatted) => write_impl
generic :: read(unformatted) => read_impl
end type a
type, extends(a) :: b
integer, public :: num2
contains
procedure :: write_impl => write_b
procedure :: read_impl => read_b
end type b
type, extends(a) :: c
end type c
contains
subroutine write_a(this, unit, iostat, iomsg)
class(a), intent(in) :: this
integer, intent(in) :: unit
integer, intent(out) :: iostat
character(*), intent(inout) :: iomsg
write(unit, iostat=iostat, iomsg=iomsg) this%num
end subroutine write_a
subroutine read_a(this, unit, iostat, iomsg)
class(a), intent(inout) :: this
integer, intent(in) :: unit
integer, intent(out) :: iostat
character(*), intent(inout) :: iomsg
read(unit, iostat=iostat, iomsg=iomsg) this%num
end subroutine read_a
subroutine write_b(this, unit, iostat, iomsg)
class(b), intent(in) :: this
integer, intent(in) :: unit
integer, intent(out) :: iostat
character(*), intent(inout) :: iomsg
write(unit, iostat=iostat, iomsg=iomsg) this%num, this%num2
end subroutine write_b
subroutine read_b(this, unit, iostat, iomsg)
class(b), intent(inout) :: this
integer, intent(in) :: unit
integer, intent(out) :: iostat
character(*), intent(inout) :: iomsg
read(unit, iostat=iostat, iomsg=iomsg) this%num, this%num2
end subroutine read_b
end module m
program mwe
use m
implicit none
class(a), allocatable :: o1, o2, o3, o4
class(container), allocatable :: arr(:)
integer :: i, arr_size, tmp
character(20) :: str_tmp
o1 = b('b', 1, 2)
o2 = c('c', 3)
allocate(arr(2))
arr(1)%item = o1
arr(2)%item = o2
select type(t => o1)
type is(b)
write(*,*) t%num, t%num2
end select
select type(t => arr(1)%item)
type is(b)
write(*,*) t%num, t%num2
end select
write(*,*) 'Write into binary'
! WRITE size
open(123, file='test5.dat', form='unformatted')
write(123) SIZE(arr)
do i=1,2
write(123) arr(i)%item%obj_type
if(arr(i)%item%obj_type .eq. 'b') then
select type(t => arr(i)%item)
type is(b)
write(123) t
end select
else if(arr(i)%item%obj_type .eq. 'c') then
select type(t => arr(i)%item)
type is(c)
write(123) t
end select
end if
end do
close(123)
write(*,*) 'Read from binary'
open(123, file='test5.dat', form='unformatted')
read(123) arr_size
write(*,*) 'array size: ', arr_size
do i=1,2
read(123) str_tmp
write(*,*) str_tmp
if(allocated(o3)) deallocate(o3)
if(str_tmp .eq. 'b') then
allocate(b :: o3)
select type(t => o3)
type is(b)
read(123) t
write(*,*) t%num, t%num2 ! BAD OUTPUT
end select
else if(str_tmp .eq. 'c') then
allocate(c :: o3)
select type(t => o3)
type is(c)
read(123) t
write(*,*) t%num
end select
end if
end do
end program mwe
问题是,读取 o1
- 它是类型 b
,即这个对象有两个组件 - num
和 num2
。我存储它,我自然希望读取值与写入值相同。
但我遇到了与 中描述的相同的奇怪行为。在那个问题中,它是由初始化数组时错误的赋值语法引起的,但在这种情况下,我完全不知道为什么我的输出看起来像这样:
1 2
1 2
Write into binary
Read from binary
array size: 2
b
1 0
c
3
b
下的值显然应该是1和2,而不是1和0,我哪里做错了?
这里的问题是在
select type(t => arr(i)%item)
type is(b)
write(123) t
end select
ifort 实际上并未选择程序 write_b
来处理定义的输出。在处理定义的输入时,它也没有选择过程 read_b
。
而是选择了过程 write_a
和 read_a
。
这是编译器的问题,应该报告给英特尔。一个相当繁琐的解决方法是在这些过程中 select type
。
我正在尝试编写一个简单的代码,它获取一些具有相同父抽象的对象 class,将它们存储到一个二进制文件中并读回它们。
我的代码如下所示:
module m
implicit none
type :: container
class(a), allocatable :: item
end type container
type, abstract :: a
character(20), public :: obj_type
integer, public :: num
contains
procedure :: write_impl => write_a
procedure :: read_impl => read_a
generic :: write(unformatted) => write_impl
generic :: read(unformatted) => read_impl
end type a
type, extends(a) :: b
integer, public :: num2
contains
procedure :: write_impl => write_b
procedure :: read_impl => read_b
end type b
type, extends(a) :: c
end type c
contains
subroutine write_a(this, unit, iostat, iomsg)
class(a), intent(in) :: this
integer, intent(in) :: unit
integer, intent(out) :: iostat
character(*), intent(inout) :: iomsg
write(unit, iostat=iostat, iomsg=iomsg) this%num
end subroutine write_a
subroutine read_a(this, unit, iostat, iomsg)
class(a), intent(inout) :: this
integer, intent(in) :: unit
integer, intent(out) :: iostat
character(*), intent(inout) :: iomsg
read(unit, iostat=iostat, iomsg=iomsg) this%num
end subroutine read_a
subroutine write_b(this, unit, iostat, iomsg)
class(b), intent(in) :: this
integer, intent(in) :: unit
integer, intent(out) :: iostat
character(*), intent(inout) :: iomsg
write(unit, iostat=iostat, iomsg=iomsg) this%num, this%num2
end subroutine write_b
subroutine read_b(this, unit, iostat, iomsg)
class(b), intent(inout) :: this
integer, intent(in) :: unit
integer, intent(out) :: iostat
character(*), intent(inout) :: iomsg
read(unit, iostat=iostat, iomsg=iomsg) this%num, this%num2
end subroutine read_b
end module m
program mwe
use m
implicit none
class(a), allocatable :: o1, o2, o3, o4
class(container), allocatable :: arr(:)
integer :: i, arr_size, tmp
character(20) :: str_tmp
o1 = b('b', 1, 2)
o2 = c('c', 3)
allocate(arr(2))
arr(1)%item = o1
arr(2)%item = o2
select type(t => o1)
type is(b)
write(*,*) t%num, t%num2
end select
select type(t => arr(1)%item)
type is(b)
write(*,*) t%num, t%num2
end select
write(*,*) 'Write into binary'
! WRITE size
open(123, file='test5.dat', form='unformatted')
write(123) SIZE(arr)
do i=1,2
write(123) arr(i)%item%obj_type
if(arr(i)%item%obj_type .eq. 'b') then
select type(t => arr(i)%item)
type is(b)
write(123) t
end select
else if(arr(i)%item%obj_type .eq. 'c') then
select type(t => arr(i)%item)
type is(c)
write(123) t
end select
end if
end do
close(123)
write(*,*) 'Read from binary'
open(123, file='test5.dat', form='unformatted')
read(123) arr_size
write(*,*) 'array size: ', arr_size
do i=1,2
read(123) str_tmp
write(*,*) str_tmp
if(allocated(o3)) deallocate(o3)
if(str_tmp .eq. 'b') then
allocate(b :: o3)
select type(t => o3)
type is(b)
read(123) t
write(*,*) t%num, t%num2 ! BAD OUTPUT
end select
else if(str_tmp .eq. 'c') then
allocate(c :: o3)
select type(t => o3)
type is(c)
read(123) t
write(*,*) t%num
end select
end if
end do
end program mwe
问题是,读取 o1
- 它是类型 b
,即这个对象有两个组件 - num
和 num2
。我存储它,我自然希望读取值与写入值相同。
但我遇到了与
1 2
1 2
Write into binary
Read from binary
array size: 2
b
1 0
c
3
b
下的值显然应该是1和2,而不是1和0,我哪里做错了?
这里的问题是在
select type(t => arr(i)%item)
type is(b)
write(123) t
end select
ifort 实际上并未选择程序 write_b
来处理定义的输出。在处理定义的输入时,它也没有选择过程 read_b
。
而是选择了过程 write_a
和 read_a
。
这是编译器的问题,应该报告给英特尔。一个相当繁琐的解决方法是在这些过程中 select type
。