Cannot instantiate ctype 'struct *' of unknown size

[Yicong Huang]

Hi,

The below is the code we met troubles;

ffi.cdef('''

  struct API {

     struct api_ret* (*pyudf)(char* str);

  };

''')

ffi.cdef('''

  struct api_ret {

     char *ret1;

     char *ret2;

     char *ret3;

  };

''')

result = ffi.new('struct api_ret*')

At first, we defined struct API with a function pointer that return a pointer to struct api_ret.

And then we defined api_ret, and tried to new the object.

The problem seems to happen when the function pointer and new structure are together.

The below code had no problems.

ffi.cdef('''

  struct API {

     struct api_ret* (*pyudf)(char* str);

  };

''')

ffi.cdef('''

  struct api_ret2 {

     char *ret1;

     char *ret2;

     char *ret3;

  };

''')

#we used different name api_ret2 to work around the issue.

result = ffi.new('struct api_ret2*')

[Yicong Huang]

Oh, great thanks for you help!

Finally, I found out the real issue.

The whold code is this:

@ffi.callback("struct api_ret*(char *)")

def udf_api(arg0):

   return None

ffi.cdef('''

  struct API {

     struct api_ret* (*pyudf)(char* str);

  };

''')

ffi.cdef('''

  struct api_ret {

     char *ret1;

     char *ret2;

     char *ret3;

  };

''')

result = ffi.new('struct api_ret*')

And we should put the function callback annotion below struct api_ret definition. :)

On Wed, May 20, 2015 at 5:51 PM, Amaury Forgeot d'Arc <amau...@gmail.com> wrote:

2015-05-20 11:44 GMT+02:00 Yicong Huang <hengh...@gmail.com>:

Hi,

The below is the code we met troubles;

ffi.cdef('''

  struct API {

     struct api_ret* (*pyudf)(char* str);

  };

''')

ffi.cdef('''

  struct api_ret {

     char *ret1;

     char *ret2;

     char *ret3;

  };

''')

result = ffi.new('struct api_ret*')

This code works for me. What's the issue exactly?

 

At first, we defined struct API with a function pointer that return a pointer to struct api_ret.

And then we defined api_ret, and tried to new the object.

The problem seems to happen when the function pointer and new structure are together.

The below code had no problems.

ffi.cdef('''

  struct API {

     struct api_ret* (*pyudf)(char* str);

  };

''')

ffi.cdef('''

  struct api_ret2 {

     char *ret1;

     char *ret2;

     char *ret3;

  };

''')

#we used different name api_ret2 to work around the issue.

result = ffi.new('struct api_ret2*')

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--

Amaury Forgeot d'Arc