Re: [LAD] [LAU] cancelling I/O with libsndfile

On Tue, Jun 14, 2011 at 01:01:09PM +0300, Dan Muresan wrote: 'Work around it' coild mean something entirely different : not trying to cancel anything, by using a system that doesn't require it. More below. It's probably a Good Thing (TM) that libsndfile doesn't do its own buffering. First, the file system will do buffering, and if you're playing a sound file probably decide it should read ahead. Second, any application that wants to use audio data in real time will need to do its own buffering, typically a few seconds. How exactly this is organised will be application dependent. Having a third layer in between this and the system is not going to help. If you support things like loops, random locates, shutthling, scrubbing, etc. the buffer management logic required to support all of this in an efficient way may become complicated. But only the application can do it. One way to organise the buffer is to divide it in fragments of say 1/4 second, and have the start offset of each one quantised to the same value. The syscall overhead becomes trivial for such a lenght. When you need new fragments, you send commands to the reader thread to read them. If the requirements change before they are read, you can still cancel all but one of them (you cancel the requests, not the actual read() call). The one you can't cancel is no big deal, just let it happen. It will take little time compared to what has to be done anyway. Ciao, -- FA