在Fortran中读取文件中的列时，g++会给出`未定义的符号："__gfortran_set_args"`

Question

我正在尝试从Fortran的输入文件中读取列，以便将它们用于其他计算。

当我使用g ++编译时，我读到了这个错误：

 Undefined symbols for architecture x86_64:
  "__gfortran_set_args", referenced from:
      _main in ccOO2MBV.o
  "__gfortran_set_options", referenced from:
      _main in ccOO2MBV.o
  "__gfortran_st_close", referenced from:
      _MAIN__ in ccOO2MBV.o
  "__gfortran_st_open", referenced from:
      _MAIN__ in ccOO2MBV.o
  "__gfortran_st_read", referenced from:
      _MAIN__ in ccOO2MBV.o
  "__gfortran_st_read_done", referenced from:
      _MAIN__ in ccOO2MBV.o
  "__gfortran_transfer_real", referenced from:
      _MAIN__ in ccOO2MBV.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status

我哪里错了？代码是这样的：

program columns

  INTEGER,SAVE :: lun
  INTEGER, PARAMETER :: ARRAYLEN=1440
  CHARACTER :: filename
  DOUBLE PRECISION, DIMENSION (1044) :: X_halo, Y_halo, Z_halo
  INTEGER :: i

  lun=1
  filename = 'xyz.dat'

  OPEN (1, FILE='xyz.dat',STATUS='old', ACTION='read', iostat=istat)

    do i=1,1440
       READ (1, iostat=istat) X_halo(i), Y_halo(i), Z_halo(i)
    end do

  CLOSE (1)

end program columns

Answer 1

正如@d_1999所指出的，编译器应该是gfortran，而不是g++。

除此之外，将@Ross的注释更改为答案，您的代码应该以指定的READ格式运行，此处如下所示

READ (1, *, iostat=istat) X_halo(i), Y_halo(i), Z_halo(i)

提供运行代码所需的最小更改。除此之外，还可以看看这里实现的其他差异：

program columns
  ! Add implicit none to catch that `istat` is not declared
  IMPLICIT NONE

  INTEGER,SAVE :: lun
  INTEGER, PARAMETER :: ARRAYLEN=1440
  ! Make `filename` bigger than a single character
  CHARACTER(120) :: filename
  ! can add `ARRAYLEN` here
  DOUBLE PRECISION, DIMENSION (ARRAYLEN) :: X_halo, Y_halo, Z_halo
  ! Have added `istat` here
  INTEGER :: i, istat

  lun=1
  filename = 'xyz.dat'
  ! Have replaced `xyz.dat` with `filename` and using a higher `UNIT` number
  OPEN (UNIT=10, FILE=filename, STATUS='old', ACTION='read', IOSTAT=istat)

    ! Using `ARRAYLEN` for the loop.
    ! I've also capitalised the keywords (matter of preference)
    DO i=1,ARRAYLEN
       ! And the important format specifier
       READ (10, *, iostat=istat) X_halo(i), Y_halo(i), Z_halo(i)
    END DO

  CLOSE (10)

end program columns

其中一些问题(例如，filename不够大)可以通过使用-Wall标志进行编译来捕获，例如

gfortran -Wall columns.f90 -o columns.exe