> I am new to cython. I am currently trying to make a python wrapper to use
> NASA CDF library. This is currently for practicing purposes, but hopefully
> it will eventually work out and turn into something useful.

> Anyway, for now I am trying to translate the following c codes to cython
> codes.
> ------------------------ below is from cdf.h
> ------------------------------------------------
> typedef void *CDFid;
> typedef long CDFstatus;

> static double *TT2000NULL = 0;

> #define HOST_ENCODING           8L
> #define ROW_MAJOR       1L
> #define SINGLE_FILE     1L

> ----------------------------- below is from an example, say, example.c
> -----------------------
> CDFid       test_id;                    /* CDF identifier (handle). */
> CDFstatus   status;                     /* Status returned from CDF library.
> */
> static char CDFname[] = {"test1"};      /* File name of the CDF. */
> long        numDims = 2;                /* Number of dimensions. */
> static long dimSizes[2] = {100,200};    /* Dimension sizes. */
> long        encoding = HOST_ENCODING;   /* Data encoding. */
> long        majority = ROW_MAJOR;       /* Variable data majority. */
> long        form = SINGLE_FILE;         /* Format of CDF. */

> Below is my translation.
> ------------------------------ below is from nasacdf.pxd
> ----------------------------
> cdef extern from "cdf34_1-dist/include/cdf.h":
>     ctypedef void *CDFid;
>     ctypedef long CDFstatus;
>     static double *TT2000NULL = 0;
>     enum:
>         HOST_ENCODING = 8;
>         ROW_MAJOR     = 1;
>         SINGLE_FILE   = 1;

> -------------------------------below is from test.pyx
> ------------------------------
> cimport nasacdf

> def hello():
>     cdef CDFid       test_id
>     cdef CDFstatus   status
>  #  cdef char        CDFname[] = {"test1"}
>     cdef char        *CDFname = "test1"
>     cdef long        numDims = 2
>  #  cdef static long dimSizes[2] = {100,200}
>     cdef long        encoding = HOST_ENCODING
>     cdef long        majority = ROW_MAJOR
>     cdef long        form = SINGLE_FILE

>     print CDFname

> ----------------------------- below is my setup.py ---------------------
> from distutils.core import setup
> from distutils.extension import Extension
> from Cython.Distutils import build_ext

> cdfdist = 'cdf34_1-dist/'
> modules = Extension("cdf",
>     sources = ['test.pyx'],
>     libraries = [cdfdist + 'lib/libcdf.a'],
>     extra_compile_args = ['-D_FILE_OFFSET_BITS=64', '-D_LARGEFILE64_SOURCE',
>                          '-D_LARGEFILE_SOURCE'])

> setup(name = 'pyNASACDF',
>       version = '0.1.0',
>       cmdclass = {'build_ext':build_ext},
>       ext_modules = [modules]
>      )

> ---------------------------------------- end of code
> --------------------------------------
>  I modified the CDFname declaration and commented out dimSizes declaration
> because the compiler issued errors on them. After I run:
> python setup.py build_ext --inplace
> I got errors. I attached the error message below. Can anyone tell me what is
> wrong with my translation, please? Thank you very much.

>>$ python setup.py build_ext --inplace
> running build_ext
> cythoning test.pyx to test.c

> Error compiling Cython file:
> ------------------------------------------------------------
> ...
> # File: nasacdf.pxd

> cdef extern from "cdf34_1-dist/include/cdf.h":
>     ctypedef void *CDFid;
>                        ^

> nasacdf.pxd:4:24: Syntax error in ctypedef statement

> Error compiling Cython file:
> ------------------------------------------------------------
> ...
> # File test.pyx

> cimport nasacdf

> def hello():
>     cdef CDFid       test_id
>         ^
> ------------------------------------------------------------

> test.pyx:6:9: 'CDFid' is not a type identifier

> Error compiling Cython file:
> ------------------------------------------------------------
> ...

> cimport nasacdf

> def hello():
>     cdef CDFid       test_id
>     cdef CDFstatus   status
>         ^
> ------------------------------------------------------------

> test.pyx:7:9: 'CDFstatus' is not a type identifier

> Error compiling Cython file:
> ------------------------------------------------------------
> ...
>     cdef CDFstatus   status
>  #  cdef char        CDFname[] = {"test1"}
>     cdef char        *CDFname = "test1"
>     cdef long        numDims = 2
>  #  cdef static long dimSizes[2] = {100,200}
>     cdef long        encoding = HOST_ENCODING
>                                             ^
> ------------------------------------------------------------

> test.pyx:12:45: undeclared name not builtin: HOST_ENCODING

> Error compiling Cython file:
> ------------------------------------------------------------
> ...
>  #  cdef char        CDFname[] = {"test1"}
>     cdef char        *CDFname = "test1"
>     cdef long        numDims = 2
>  #  cdef static long dimSizes[2] = {100,200}
>     cdef long        encoding = HOST_ENCODING
>     cdef long        majority = ROW_MAJOR
>                                         ^
> ------------------------------------------------------------

> test.pyx:13:41: undeclared name not builtin: ROW_MAJOR

> Error compiling Cython file:
> ------------------------------------------------------------
> ...
>     cdef char        *CDFname = "test1"
>     cdef long        numDims = 2
>  #  cdef static long dimSizes[2] = {100,200}
>     cdef long        encoding = HOST_ENCODING
>     cdef long        majority = ROW_MAJOR
>     cdef long        form = SINGLE_FILE
>                                       ^
> ------------------------------------------------------------

> test.pyx:14:39: undeclared name not builtin: SINGLE_FILE
> building 'cdf' extension
> clang -fno-strict-aliasing -fno-common -dynamic -g -Os -pipe -fno-common
> -fno-strict-aliasing -fwrapv -mno-fused-madd -DENABLE_DTRACE -DMACOSX
> -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -Os -Wall
> -Wstrict-prototypes -DENABLE_DTRACE -pipe -arch i386 -arch x86_64
> -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2. 7
> -c test.c -o build/temp.macosx-10.8-intel-2.7/test.o -D_FILE_OFFSET_BITS=64
> -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE
> clang: warning: argument unused during compilation: '-mno-fused-madd'
> test.c:1:2: error: Do not use this file, it is the result of a failed Cython
> compilation.
> #error Do not use this file, it is the result of a failed Cython
> compilation.
>  ^
> 1 error generated.
> error: command 'clang' failed with exit status 1

> -------------------------------below is from test.pyx
> cimport nasacdf

> def hello():
>     cdef CDFid       test_id
>     cdef CDFstatus   status
>  #  cdef char        CDFname[] = {"test1"}
>     cdef char        *CDFname = "test1"
>     cdef long        numDims = 2
>  #  cdef static long dimSizes[2] = {100,200}
>     cdef long        encoding = HOST_ENCODING
>     cdef long        majority = ROW_MAJOR
>     cdef long        form = SINGLE_FILE

>     print CDFname

> JBT, 28.09.2012 06:39:
> > ------------------------------ below is from nasacdf.pxd
> > cdef extern from "cdf34_1-dist/include/cdf.h":
> >     ctypedef void *CDFid;
> >     ctypedef long CDFstatus;
> >     static double *TT2000NULL = 0;
> >     enum:
> >         HOST_ENCODING = 8;
> >         ROW_MAJOR     = 1;
> >         SINGLE_FILE   = 1;

> > -------------------------------below is from test.pyx
> > cimport nasacdf

> > def hello():
> >     cdef CDFid       test_id
> >     cdef CDFstatus   status
> >  #  cdef char        CDFname[] = {"test1"}
> >     cdef char        *CDFname = "test1"
> >     cdef long        numDims = 2
> >  #  cdef static long dimSizes[2] = {100,200}
> >     cdef long        encoding = HOST_ENCODING
> >     cdef long        majority = ROW_MAJOR
> >     cdef long        form = SINGLE_FILE

> >     print CDFname

> As normal in Python, you have to either prefix the names you use with the
> module that you imported, or import the names that the module defines
> directly into your code. I.e. either use

>     cimport nasacdf

>     cdef nasacdf.CDFid test_id

> or

>     from nasacdf cimport CDFid

>     cdef CDFid test_id

> or any mix of the two as you see fit. Cython is a lot closer to Python
> than
> to C. It actually has namespaces.

> Stefan

> Thank you. That helps a lot.

> So, after changing nasacdf.pxd to cdf.pxd, I modified the cimport statement
> to:
> from cdc cimport *

> Then I got this error:
> Error compiling Cython file:
> ------------------------------------------------------------
> ...
> # File: cdf.pxd

> cdef extern from "cdf34_1-dist/include/cdf.h":
>     ctypedef void *CDFid
>     ctypedef long CDFstatus
>     static double *TT2000NULL = 0

> cdf.pxd:6:18: Syntax error in C variable declaration

> As you can see, the *static double* statement is copied from cdf.h, so I
> don't understand why cython sees that as an error. Any ideas? Thank you so
> much.

> BTW, Yichao, I removed all the semicolons per your suggestion. :-)

> JBT

> On Friday, September 28, 2012 6:47:18 AM UTC-7, Stefan Behnel wrote:

>> JBT, 28.09.2012 06:39:
>> > ------------------------------ below is from nasacdf.pxd
>> > cdef extern from "cdf34_1-dist/include/cdf.h":
>> >     ctypedef void *CDFid;
>> >     ctypedef long CDFstatus;
>> >     static double *TT2000NULL = 0;
>> >     enum:
>> >         HOST_ENCODING = 8;
>> >         ROW_MAJOR     = 1;
>> >         SINGLE_FILE   = 1;

>> > -------------------------------below is from test.pyx
>> > cimport nasacdf

>> > def hello():
>> >     cdef CDFid       test_id
>> >     cdef CDFstatus   status
>> >  #  cdef char        CDFname[] = {"test1"}
>> >     cdef char        *CDFname = "test1"
>> >     cdef long        numDims = 2
>> >  #  cdef static long dimSizes[2] = {100,200}
>> >     cdef long        encoding = HOST_ENCODING
>> >     cdef long        majority = ROW_MAJOR
>> >     cdef long        form = SINGLE_FILE

>> >     print CDFname

>> As normal in Python, you have to either prefix the names you use with the
>> module that you imported, or import the names that the module defines
>> directly into your code. I.e. either use

>>     cimport nasacdf

>>     cdef nasacdf.CDFid test_id

>> or

>>     from nasacdf cimport CDFid

>>     cdef CDFid test_id

>> or any mix of the two as you see fit. Cython is a lot closer to Python
>> than
>> to C. It actually has namespaces.

>> Stefan

>> Then I got this error:
>> Error compiling Cython file:
>> ------------------------------------------------------------
>> ...
>> # File: cdf.pxd

>> cdef extern from "cdf34_1-dist/include/cdf.h":
>>     ctypedef void *CDFid
>>     ctypedef long CDFstatus
>>     static double *TT2000NULL = 0

> don't think cython understand static (or I'm wrong?)
> and u need a cdef here

> cdef double *.... = NULL

> works fine for me

>>> Then I got this error:
>>> Error compiling Cython file:
>>> ------------------------------------------------------------
>>> ...
>>> # File: cdf.pxd

>>> cdef extern from "cdf34_1-dist/include/cdf.h":
>>>     ctypedef void *CDFid
>>>     ctypedef long CDFstatus
>>>     static double *TT2000NULL = 0

>> don't think cython understand static (or I'm wrong?)
>> and u need a cdef here

>> cdef double *.... = NULL

>> works fine for me

> The "cdef" isn't needed when you're inside of a "cdef extern" block anyway.

>>> BTW, Yichao, I removed all the semicolons per your suggestion. :-)
>> That is where the original syntax error coming from. afaik

> No, semicolons work the same way as in Python.

> Stefan

> Yichao Yu, 28.09.2012 18:45:
> > On Fri, Sep 28, 2012 at 12:32 PM, JBT wrote:
> >> So, after changing nasacdf.pxd to cdf.pxd, I modified the cimport
> statement
> >> to:
> >> from cdc cimport *

> >> Then I got this error:
> >> Error compiling Cython file:
> >> ------------------------------------------------------------
> >> ...
> >> # File: cdf.pxd

> >> cdef extern from "cdf34_1-dist/include/cdf.h":
> >>     ctypedef void *CDFid
> >>     ctypedef long CDFstatus
> >>     static double *TT2000NULL = 0

> > don't think cython understand static (or I'm wrong?)
> > and u need a cdef here

> > cdef double *.... = NULL

> > works fine for me

> The "cdef" isn't needed when you're inside of a "cdef extern" block
> anyway.

> >> BTW, Yichao, I removed all the semicolons per your suggestion. :-)
> > That is where the original syntax error coming from. afaik

> No, semicolons work the same way as in Python.

> Stefan

> On Friday, September 28, 2012 9:53:19 AM UTC-7, Stefan Behnel wrote:

>> Yichao Yu, 28.09.2012 18:45:
>> > On Fri, Sep 28, 2012 at 12:32 PM, JBT wrote:
>> >> So, after changing nasacdf.pxd to cdf.pxd, I modified the cimport
>> >> statement
>> >> to:
>> >> from cdc cimport *

>> >> Then I got this error:
>> >> Error compiling Cython file:
>> >> ------------------------------------------------------------
>> >> ...
>> >> # File: cdf.pxd

>> >> cdef extern from "cdf34_1-dist/include/cdf.h":
>> >>     ctypedef void *CDFid
>> >>     ctypedef long CDFstatus
>> >>     static double *TT2000NULL = 0

>> > don't think cython understand static (or I'm wrong?)
>> > and u need a cdef here

>> > cdef double *.... = NULL

>> > works fine for me

>> The "cdef" isn't needed when you're inside of a "cdef extern" block
>> anyway.

>> >> BTW, Yichao, I removed all the semicolons per your suggestion. :-)
>> > That is where the original syntax error coming from. afaik

>> No, semicolons work the same way as in Python.

>> Stefan

> becaseu that is how you initialize arrays in C, not Python (or Cython)
> -- remember that Cyton is closer to Python is syntax than C. For
> instance, the {} are used to defien a dcitionaly literal.

> try:

>  cdef static char        CDFname = "test1"
>  cdef static long dimSizes[2] = [100, 200]

> (though you may need a char* there -- a char is one charactor.

> (unteseted, and I'm no expert, but this is closer, for sure.)

> Chris Barker, 28.09.2012 21:36:
> > On Fri, Sep 28, 2012 at 10:32 AM, JBT wrote:
> >> So, here is another question. Cython won't compile these two
> statements:
> >>     cdef static char        CDFname[] = {"test1"}
> >>     cdef static long dimSizes[2] = {100,200}
> >> because cython sees them with syntax error. I found the corresponding c
> code
> >> (without the *cdef*) in the NASA CDF C reference manual, so I presume
> the C
> >> counterpart is correct. So, why does cython think the two statements
> are not
> >> correct?

> > becaseu that is how you initialize arrays in C, not Python (or Cython)
> > -- remember that Cyton is closer to Python is syntax than C. For
> > instance, the {} are used to defien a dcitionaly literal.

> > try:

> >  cdef static char        CDFname = "test1"
> >  cdef static long dimSizes[2] = [100, 200]

> > (though you may need a char* there -- a char is one charactor.

> > (unteseted, and I'm no expert, but this is closer, for sure.)

> Cython has no keyword "static" because all globally declared C names are
> static anyway.

> Stefan

> > becaseu that is how you initialize arrays in C, not Python (or Cython)
> > -- remember that Cyton is closer to Python is syntax than C. For
> > instance, the {} are used to defien a dcitionaly literal.

> > try:

> >  cdef static char        CDFname = "test1"
> >  cdef static long dimSizes[2] = [100, 200]

> > (though you may need a char* there -- a char is one charactor.

> > (unteseted, and I'm no expert, but this is closer, for sure.)

> Cython has no keyword "static" because all globally declared C names are
> static anyway.

> Stefan

> So, here is another question. Cython won't compile these two statements:
>     cdef static char        CDFname[] = {"test1"}
>     cdef static long dimSizes[2] = {100,200}
> because cython sees them with syntax error. I found the corresponding c code
> (without the *cdef*) in the NASA CDF C reference manual, so I presume the C
> counterpart is correct. So, why does cython think the two statements are not
> correct?

> JBT

> On Friday, September 28, 2012 9:53:19 AM UTC-7, Stefan Behnel wrote:

>> Yichao Yu, 28.09.2012 18:45:
>> > On Fri, Sep 28, 2012 at 12:32 PM, JBT wrote:
>> >> So, after changing nasacdf.pxd to cdf.pxd, I modified the cimport
>> >> statement
>> >> to:
>> >> from cdc cimport *

>> >> Then I got this error:
>> >> Error compiling Cython file:
>> >> ------------------------------------------------------------
>> >> ...
>> >> # File: cdf.pxd

>> >> cdef extern from "cdf34_1-dist/include/cdf.h":
>> >>     ctypedef void *CDFid
>> >>     ctypedef long CDFstatus
>> >>     static double *TT2000NULL = 0

>> > don't think cython understand static (or I'm wrong?)
>> > and u need a cdef here

>> > cdef double *.... = NULL

>> > works fine for me

>> The "cdef" isn't needed when you're inside of a "cdef extern" block
>> anyway.

>> >> BTW, Yichao, I removed all the semicolons per your suggestion. :-)
>> > That is where the original syntax error coming from. afaik

>> No, semicolons work the same way as in Python.

>> Stefan