Submit 'int' and 'string' arrays using ctypes (Python->C++) -

i've simple working program submits int (num_piezasin example) python function c++ function.

foo.cpp

#include <iostream>  class foo{     public:         void bar(int number){             printf("number is: %d\n", number);         } };  extern "c" {     foo* foo_new(){ return new foo(); }     void foo_bar(foo* foo, int number){ foo->bar(number); } } 

foowrapper.py

from ctypes import cdll lib = cdll.loadlibrary('./libfoo.so')  class foo(object):     def __init__(self):         self.obj = lib.foo_new()      def bar(self, num_piezas):         lib.foo_bar(self.obj, num_piezas)  num_piezas = 5     f = foo() f.bar(num_piezas) 

the thing want send int array , char array along number. tried:

foo.cpp

#include <iostream> #include <string.h>  class foo{     public:         void bar(int number, int piezas[3], char prioridades[3][20]){             printf("number is: %d\n", number);             for(int i=0;i<3;i++) {                 printf("%d", piezas[i]);             }             for(int q=0;q<3;q++) {                 printf("%s ", prioridades[q]);             }         } };  extern "c" {     foo* foo_new(){ return new foo(); }     void foo_bar(foo* foo, int number, int piezas[3], char prioridades[3][20]){ foo->bar(number, piezas, prioridades); } } 

foowrapper.py

from ctypes import cdll lib = cdll.loadlibrary('./libfoo.so')  class foo(object):     def __init__(self):         self.obj = lib.foo_new()      def bar(self, num_piezas, piezas, prioridades):         lib.foo_bar(self.obj, num_piezas, piezas, prioridades)  piezas = [1, 2, 3] prioridades = ['normal', 'baja', 'primera pieza'] num_piezas = 5     f = foo() f.bar(num_piezas, piezas, prioridades) 

the c++ file compiles correctly, when try execute python function (python foowrapper.py) error message shows up:

traceback (most recent call last):   file "foowrapper.py", line 15, in <module>     f.bar(num_piezas, piezas, prioridades)   file "foowrapper.py", line 9, in bar     lib.foo_bar(self.obj, num_piezas, piezas, prioridades) ctypes.argumenterror: argument 3: <type 'exceptions.typeerror'>: don't know how convert parameter 3 

what i'm doing wrong? need else pass int , string arrays parameters? in advance.

you can away modification :

from ctypes import c_int, c_char  ...  # create 3-int array piezas = (c_int*3)() piezas[0] = 1 piezas[1] = 2 piezas[2] = 3  # create 3-(20-char array) array prio = ((c_char*20)*3)() prio[0].value = "normal" prio[1].value = "baja" prio[2].value = "primera pieza" 

but since you're dealing char arrays in c++ side part, advise change function defintion : void bar( int num, char* piezas, int len_piezas, char** prio , int len_prio_elem, int prio);. longer, have control length of input arrays if want avoid buffer overflows.