fortran - 什么是 : 'iunit' is used uninitialized in this function [-Wuninitialized]

Question

我正在使用:

  open(iunit,file=dexfile,status='old',iostat=status)
   if(status /= 0)then
     write(*,*) 'Unable to open dex file'
   endif

在 Geany 中，但出现此错误:

Warning: 'iunit' is used uninitialized in this function [-Wuninitialized]

Answer 1

如果您的编译器有此选项，您可以在函数 open 中使用 newunit 命令在打开时将标志返回到可用单元 ID:

open(newunit=iunit,file=dexfile,status='old',iostat=status)

在这种情况下，open 命令将返回一个 iunit 值作为该调用的输出，而不是输入.

否则，您可以编写一个为您执行此操作的代码片段，例如:

! Find a logical unit which is not currently in use
integer function first_available_unit() result(iunit)
   logical :: is_open
   
   do iunit=10,999 ! Skip units 1-10 as they're sometimes system reserved
      inquire(unit=iunit,opened=is_open)
      if (.not.is_open) return
   end do
end function first_available_unit

然后运行:

   iunit = first_available_unit()
   open(unit=iunit,file=dexfile,status='old',iostat=status)