一个Windows平台下Fortran多线程程序的诡异结果

[laughcry2002]

一个openmp多线程程序出现的异常结果。最小的示例代码附后。平台：Windows 7 (64 bit), Intel Fortran 编译器(版本附后）

代码 : test_omp.f90

module my_omp_mod
   use omp_lib
   implicit none
   public
   
   integer :: idt, num_threads

contains

   subroutine init()
      implicit none

      num_threads = omp_get_num_threads()
      idt         = omp_get_thread_num()

      write(*, *) "in init(): idt,  num_threads  = ", idt, num_threads, omp_get_thread_num()
   end subroutine

end module

program main
   use omp_lib
   use my_omp_mod
   implicit none

   integer :: idt2, num_threads2

!$OMP parallel default(none) private(idt2, num_threads2) private(idt, num_threads)

   call init()
	write(*, *) "in main(): idt,  num_threads  = ", idt, num_threads, omp_get_thread_num()
    
   num_threads2 = omp_get_num_threads()
   idt2         = omp_get_thread_num()
	write(*, *) "in main(): idt2, num_threads2 = ", idt2, num_threads2, omp_get_thread_num()
	
!$OMP end parallel
end program

编译：

引用

D:\>ifort -openmp test_omp.f90
Intel(R) Visual Fortran Compiler XE for applications running on IA-32, Version 14.0.2.176 Build 20140130
Copyright (C) 1985-2014 Intel Corporation. All rights reserved.

Microsoft (R) Incremental Linker Version 9.00.21022.08
Copyright (C) Microsoft Corporation. All rights reserved.

-out:test_omp.exe
-subsystem:console
-defaultlib:libiomp5md.lib
-nodefaultlib:vcomp.lib
-nodefaultlib:vcompd.lib
test_omp.obj

运行：

引用

D:\>set OMP_NUM_THREADS=2

D:\>test_omp.exe
in init(): idt, num_threads = 0 2 0
in main(): idt, num_threads = 0 0 0
in main(): idt2, num_threads2 = 0 2 0
in init(): idt, num_threads = 1 2 1
in main(): idt, num_threads = 0 0 1
in main(): idt2, num_threads2 = 1 2 1

异常出在 module 中定义的 idt 变量取值，在 openmp 指导语句中声明为 private 了，但结果似乎表明在 main 中各线程共享了同一个值（而在 init() 内却是正常的）。

谁能帮忙解释一下？