Portable ctypes.c_char_p for python 2.x and 3.x -

from ctypes documentation of python 2.x, have:

>>> printf("string '%s', int %d, double %f\n", "hi", 10, 2.2) 

and ctypes documentation of python 3.x, have:

>>> printf(b"string '%s', int %d, double %f\n", b"hi", 10, 2.2) 

so in 1 case argtypes c_char_p requires str input, while in second case requires bytes. how should write function handle both python 2.x , python 3.x ?

typical scenario is:

my_c_func.argtypes = [ c_char_p ] if __name__ == '__main__':   import sys   filename = sys.argv[1];   my_c_func( filename ) 

those types equivalent. in c strings arrays or pointers char type (each char represented 1 byte). in python 3 closest data type bytes. strings in python 3 encoded using utf-8, each char not guaranteed 1 byte. whereas, in python 2 strings typically encoded using latin-1 (depends on locale believe) -- 1 char, 1 byte.

to write code works regardless of interpreter version should write b"your string". creates str object in python 2 , bytes object in python 3. conversely guarantee unicode string use u"your string". creates unicode object in python 2 , str object in python 3.