in_stream.py 文件源码

def logging_file_preallocation_size(self):
        """
        long: Specifies a size in samples to be used to pre-allocate
            space on disk.  Pre-allocation can improve file I/O
            performance, especially in situations where multiple files
            are being written to disk.  For finite tasks, the default
            behavior is to pre-allocate the file based on the number of
            samples you configure the task to acquire.
        """
        val = ctypes.c_ulonglong()

        cfunc = lib_importer.windll.DAQmxGetLoggingFilePreallocationSize
        if cfunc.argtypes is None:
            with cfunc.arglock:
                if cfunc.argtypes is None:
                    cfunc.argtypes = [
                        lib_importer.task_handle,
                        ctypes.POINTER(ctypes.c_ulonglong)]

        error_code = cfunc(
            self._handle, ctypes.byref(val))
        check_for_error(error_code)

        return val.value