On Jul 21, 2009, at 10:47 PM, Peter Alexander wrote:
> Hi all,
>
> I'm getting a cython build[1] error[2] from the following code
> snippet[3].
> A test file[4] using a similar implementation (stack memory only)
> built fine.
> Could you help me see what I'm doing wrong here.
Cython variable semantics are just like they are in Python,
specifically, note that you are assigning to mp_head in that function.
mp_head = mp_cur
This makes mp_head into a local variable (and, since you haven't
specified a type, of type object). Just like Python, if you want to
assign to a global variable, you need to put "global mp_head" in your
function body.
To make this error more clear, it would be a good idea to emit a
warning that mp_head is being used before it is defined.
- Robert
> I'm using repo: cython-devel changeset: 2094:bcc850a1253a date: Mon
> Jul 20 15:40:26 2009 -0700
> Thanks ~Pete
>
> [1] ####### build.sh script ##########
>
> cython -a -I/home/travlr/src/numpy.gitsvn/doc/cython/ "$1"
>
> gcc -shared -pthread -fPIC -fwrapv -O2 -Wall -fno-strict-aliasing -
> std=c99\
> -I/usr/include/python2.6 -o ${1%\.*}.so ${1%\.*}.c
>
> ######## end build.sh script ########
>
> [2] ######## build error message ########
>
> $ ./build utils.pyx
>
> Error converting Pyrex file to C:
> ------------------------------------------------------------
> void* mmalloc(size_t size, size_t n_items):
> cdef:
> MemPoolItem* mp_cur = <MemPoolItem*>malloc(sizeof
> (MemPoolItem))
> mp_cur.memory = malloc(size * n_items)
> mp_cur.next = mp_head
> ^
> ------------------------------------------------------------
> /home/travlr/py/cy/utils.pyx:14:29: Cannot convert Python object to
> 'MemPoolItem *'
>
> [...]
>
> ######## end build error message ###########
>
> [3] ######## code snippet #########
>
> from defs cimport *
>
> cdef:
> struct MemPoolItem:
> void* memory
> MemPoolItem* next
>
> MemPoolItem* mp_head=NULL
>
> void* mmalloc(size_t size, size_t n_items):
> cdef:
> MemPoolItem* mp_cur = <MemPoolItem*>malloc(sizeof
> (MemPoolItem))
> mp_cur.memory = malloc(size * n_items)
> mp_cur.next = mp_head
> mp_head = mp_cur
> return mp_cur.memory
>
> mfree():
> cdef:
> MemPoolItem* mp_cur = mpi_head
> MemPoolItem* mp_tmp = NULL
> while mp_cur:
> free(mp_cur.memory)
> mp_cur.memory = NULL
> mp_tmp = mpi_cur.next
> free(mpi_cur)
> mp_cur = mpi_tmp
> mp_head = NULL
>
> ######## end code snippet #########
>
> [4] ######## test file #########
>
> cdef:
> struct S_t:
> int val
> S_t* next
>
> S_t s
>
> _run():
> s.val = 345
> print s.val
>
> def run():
> _run()
>
> ########### end test file ############
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