Hi everybody, I am currently playing around with ctypes and a C library (libWand from ImageMagick), and as I want to easily deploy it on Mac, Linux and Windows, I prefer a ctypes solution over a C module. At least on windows, I would have resource problems to compile the C module. So, ctypes is the perfect choice for me.
But I am currently encountering a pattern inside the C library, that has to be used to free memory. Coding in C I have to do the following char *description; long severity; description = MagickGetException(wand, &severity); /* do something with the description: print it, log it, ... */ description = (char *) MagickRelinquishMemory(description); exit(-1); /* or something else what I want to after an exception occured */ So, this looks easy and is sensible from C's point of view. Now I try to translate this to Python and ctypes. dll.MagickGetException.argtypes = [c_long, POINTER(c_long)] dll.MagickGetException.restype = c_char_p severity = c_long() description = dll.MagickGetException(byref(severity)) # So far so good. The above works like a charm, but the problem follows now # ctypes already converted the char * for description to a String object. # That means description has arrived in an area under Python's control. # these definitions are the easy part dll.MagickRelinquishMemory.argtypes = [c_void_p] dll.MagickRelinquishMemory.restype = c_char_p # but this obviously must cause problems and causes problems dll.MagickRelinquishMemory(description) So, my question is, how do I deal with this situation? Can I ignore the call to MagickRelinquishMemory, cause Python takes care of the resources already? Or is it impossible to use it at all, and I have to think about a different solution? Best regards, Oliver -- Oliver Andrich <[EMAIL PROTECTED]> --- http://roughbook.de/ -- http://mail.python.org/mailman/listinfo/python-list