使用ctypes在Python中使用Fortran可选参数

我应该如何使用CType正确处理Python中的可选Fortran参数？例如,让我们假设Fortran子例程看起来像：

MODULE test_module
INCLUDES
   SUBROUTINE fstr_test(iunit, istat, file1, file2, file3, test, file4, file5)
      IMPLICIT NONE
      INTEGER, INTENT(inout) :: iunit
      INTEGER, INTENT(out) :: istat
      CHARACTER(LEN=*), INTENT(in) :: file1, file2, file3
      CHARACTER(LEN=*), INTENT(in), OPTIONAL :: file4, file5
      INTEGER, OPTIONAL :: test
      WRITE(6,*) file1, file2, file3
      RETURN
   END SUBROUTINE fstr_test
END MODULE test_module

现在python应该看起来像

import ctypes as ct
libtest = ct.cdll.LoadLibrary("libtest.so")
fstr_h = getattr(libtest,'__test_module_MOD_fstr_test')
fstr_h.argparse =     [ ct.c_int, \ #iunit
                        ct.c_int, \ #istat
                        ct.c_char_p, \ #file1
                        ct.c_char_p, \ #file2
                        ct.c_char_p, \ #file3
                        ct.c_int, \ #test
                        ct.c_char_p,\ #file4
                        ct.c_char_p, \ #file5
    ct.c_bool, ct.c_bool, ct.c_bool,\ # Three optional arguments
    ct.c_long, ct.c_long, ct.c_long, ct.c_long, ct.c_long] # lengths
fstr_h.restype=None
iunit_temp = ct.c_int(0)
istat_temp = ct.c_int(0)
record_in_temp = ct.c_int(0)
opt1 = ct.c_bool(True)
opt2 = ct.c_bool(True)
opt3 = ct.c_bool(True)
file1 = "one"
file2 = "two"
file3 = "three"
file4 = "four"
file5 = "five"
fstr_h(iunit_temp,ct.byref(istat_temp), \
    file1.encode('UTF-8'),file2.encode('UTF-8'),file3.encode('UTF-8'),\
    record_in_temp,file4.encode('UTF-8'),file5.encode('UTF-8'), \
    ct.byref(opt1), ct.byref(opt2), ct.byref(opt3),\
    len(file1),len(file2),len(file3),len(file4),len(file5))

从gcc关于其argument passing conventions的文档中我相信我正确地传递了变量,但可能有一些我遗漏的微妙之处？当我尝试运行代码时,它会崩溃.

解决方法:

好的想出了一些事情.

>我需要使用不是argparse的argtypes
>可选参数只有在Fortran中定义为由VALUE传递时才需要隐藏的逻辑变量.如果它们没有被传递,那么仍然需要传递NULL指针.
>所有整数都需要通过引用传入.

所以Fortran代码仍然如上所述,但Python代码应该是这样的

import ctypes as ct
libtest = ct.cdll.LoadLibrary("libtest.so")
fstr_h = getattr(libtest,'__test_module_MOD_fstr_test')
fstr_h.argtypes =     [ ct.POINTER(ct.c_int), \ #iunit
                        ct.POINTER(ct.c_int), \ #istat
                        ct.c_char_p, \ #file1
                        ct.c_char_p, \ #file2
                        ct.c_char_p, \ #file3
                        ct.POINTER(ct.c_int), \ #test
                        ct.c_char_p,\ #file4
                        ct.c_char_p, \ #file5
                        ct.c_long, ct.c_long, ct.c_long, ct.c_long, ct.c_long] # lengths
fstr_h.restype=None
iunit_temp = ct.c_int(0)
istat_temp = ct.c_int(0)
record_in_temp = ct.c_int(0)
file1 = "one"
file2 = "two"
file3 = "three"
file4 = "four"
file5 = "five"
fstr_h(ct.byref(iunit_temp),ct.byref(istat_temp), \
       file1.encode('UTF-8'),file2.encode('UTF-8'),file3.encode('UTF-8'),\
       ct.byref(record_in_temp),file4.encode('UTF-8'),file5.encode('UTF-8'), \
       len(file1),len(file2),len(file3),len(file4),len(file5))

现在这是猜想,但我怀疑任何在Fortran中输入为INTNET(in)的变量都可以作为值而不是指针传递.但是,由于INTENT(inout)和INTENT(out)变量的值已更改,我认为需要通过指针传递. Fortran中经常输入的参数也可以这么说.

标签：python,fortran,ctypes,gfortran
来源： https://codeday.me/bug/20190701/1347613.html