[文件读写] 又是‘end of file’的报错，但是这个错误不影响程序运行

Program t
  Implicit None
  Real :: a(3)       
  Real :: b(3) 
  Character(10) :: cha
  Integer :: ioerr
  Open(11,file='in.txt',iostat=ioerr)
  Open(12,file='out1.txt')
  Do
    Read(11,*) cha
    If (cha(1:) == 'vector_a') Then
      Write(*,*) cha
      Read(11,*) a(:)
      Write(12,*) 'a:', a(:)
    Endif
    If (cha(1:) == 'vector_b') Then
      Write(*,*) cha
      Read(11,*) b(:)
      Write(12,*) 'b:', b(:)
    Endif
    If (ioerr/=0) Exit
  Enddo
  Close(11)
End Program t