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POProblem running functions from a DLL file using ctypes in Object-oriented Python
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copied!<p>I sure hope this won't be an already answered question or a stupid one. Recently I've been programming with several instruments. Trying to communicate between them in order to create a testing program. However I've encoutered some problems with one specific instrument when I'm trying to call functions that I've "masked" out from the instruments DLL file. When I use the interactive python shell it works perfectly (although its alot of word clobbering). But when I implement the functions in a object-oriented manner the program fails, well actually it doesn't fail it just doesn't do anything. This is the first method that's called: (ctypes and ctypes.util is imported)</p> <pre><code> def init_hardware(self): """ Inits the instrument """ self.write_log("Initialising the automatic tuner") version_string = create_string_buffer(80) self.error_string = create_string_buffer(80) self.name = "Maury MT982EU" self.write_log("Tuner DLL path: %s", find_library('MLibTuners')) self.maury = WinDLL('MlibTuners') self.maury.get_tuner_driver_version(version_string) if (version_string.value == ""): self.write_log("IMPORTANT: Error obtaining the driver version") else: self.write_log("Version number of the DLL: %s" % version_string.value) self.ThreeTypeLong = c_long * 3 </code></pre> <p>Now that works swell, everything is perfect and I get perfect log-entries. But when I try to run a method further into the program called:</p> <pre><code>def add_tuner_and_controller(self, name, serial_number, tuner_number=0): """ Adds the tuner to the driver object, controller is inside the tuner """ self.write_log("Adding tuner %d and the built-in controller" % tuner_number) TempType = self.ThreeTypeLong() self.maury.add_controller(c_short(tuner_number), c_char_p(self.file_path), c_char_p(name), c_int(0), c_int(0), c_long(0), c_short(serial_number), self.error_string) self.maury.add_tuner(c_short(tuner_number), c_char_p(name), c_short(serial_number), c_short(0), c_short(1), pointer(c_double()), TempType, pointer(c_double()), pointer(c_double()), pointer(c_double()), self.error_string) </code></pre> <p>The program suddenly stops working/keeps running , nothing happenes when the "self.maury"-line is called. When I place everything in the init_hardware method it works perfectly so I'm guessing there's a slight memory "error" or something with the objective oriented structure. I really want it to remain this way, is there anyway to isolate the functions in this manner? or do I have to restrict myself to a big chunk of code?</p> <hr> <p><strong>EDIT:</strong><br> <em>Documentation info</em>:<br> [Legend: The stars indicate pointers and the brackets indicate arrays]</p> <p><strong>The add_tuner function adds or updates one tuner in the tuner driver object.</strong></p> <pre><code>short add_tuner(short tuner_number, char model[ ], short serial_number, short ctlr_num, short ctlr_port, short *no_of_motors, long max_range[ ], double *fmin, double *fmax, double *fcrossover, char error_string[ ]) </code></pre> <p><strong>Output</strong>: <code>no_motors, max_range (array of three numbers), fmin, fmax, fcrossover,error_string (80+ characters long), function-return->Error flag</code></p> <p><br> <br> <strong>The add_controller function adds or updates one controller in the tuner driver object</strong></p> <pre><code>short add_controller(short controller_number, char driver[ ], char model[ ], int timeout, int address, long delay_ms, char error_string[ ]) </code></pre> <p><strong>Output</strong>: <code>error_string, function-return->Error flag</code></p>

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