How do you convert a char * with 0-value bytes into a python string?
ctypes, python
Solution
As you said, use a `POINTER(c_char)` to get a pointer to the array of binary data. To put that together into a string, you can just take a slice of it, since array indexing works as expected with ctypes pointers:
clibblah = ctypes.cdll.LoadLibrary('clibblah.dylib')
get_pixels = clibblah.get_pixels
get_pixels.restype = ctypes.POINTER(ctypes.c_char)
pixels = get_pixels()
num_pixels = clibblah.get_pixel_length()
# Slice the ctypes array into a Python string
a = pixels[:num_pixels]
Problem
Using the ctypes module I can easily import a POINTER(c_char) or a c_char_p type into python, but neither of these provides a way to end up with a python string that contains zero value bytes. c_char_p is zero terminated, meaning that a char * array from C is terminated at the first zero value. POINTER(c_char) is the recommended way of importing binary data that can have 0 values, but there doesn't seem to be a way to directly convert this into a python string. I can do this: ``` pixels = clibblah.get_pixels() a = "" for i in range(0, clibblah.get_pixel_length()): a += pixels[i] ``` ...but this 1) doesn't seem very pythony, and 2) takes forever (converting a 640x480 block of pixel data takes about 2 seconds on my mac). I've seen a bunch of questions regarding this on stack overflow, but darned if I can see one that isn't either people going "why do you need to do that?" or "c_char_p will do what you want" (it doesn't, as I've described above). The only credible advice I've seen is to use the c api PyString_FromStringAndSize, as recommended here: http://www.cosc.canterbury.ac.nz/greg.ewing/python/Pyrex/version/Doc/FAQ.html Can't really see how that helps though, because afaik that's a cython feature, not a python one. For the interested, the reason I need to do this is I'm working with panda3d and a kinect, and the kinect c api provides an array of unsigned char * values and the panda3d api lovingly provides a setPixels() call that only takes a python string as an argument.