[LAD] jack ringbuffer usage

Hi, I'm trying to use jack's ringbuffer like this: - initialization: jack_ringbuffer_t * ringBuf = jack_ringbuffer_create(sizeof(jack_default_audio_sample_t) * (1<<16)); memset (ringBuf->buf, 0, ringBuf->size) ; - jack process callback: jack_default_audio_sample_t buf[numChannels]; size_t read_cnt = 0; for (_frameCounter=0; _frameCounter < nFrames; _frameCounter++) { read_cnt = jack_ringbuffer_read(ringBuf, (void*)buf, sample_size * numChannels); ^^^^^^^^^ error } but g++ won't compile the code and report this error: invalid conversion from 'void*' to 'char*' [-fpermissive] /usr/local/include/jack/ringbuffer.h:136: error: initializing argument 2 of 'size_t jack_ringbuffer_read(jack_ringbuffer_t*, char*, size_t)' [-fpermissive] passing -fpermissive gets the program running but is it the right way to do it? Thanks -- Raphaël.