some question about snprintf

[Greg KH]

On Sun, Feb 06, 2011 at 05:23:01PM +0800, loody wrote:
> hi:
> 
> 2011/2/6 loody <miloody at gmail.com>:
> > hi all:
> > I want to use snprintf for collecting debug message and print it later.
> > But I found :
> > 1. when I add "\n" as below, the buffer will be cleared, that means
> > the "irq status" will put at the head of Buffer instead of at the end
> > of "ehci work".
> >    Size -= snprintf (Buffer , Size,"ehci_work\n");
> >    Size -= snprintf (Buffer , Size,"irq status 0x%x\n",status);
> > is it possible to add "\n" in the buffer, but will will not reset the buffer?
> >
> > 2. instead of snprintf, is there any better idea for saving debug
> > message and show it out later?
> 3. is there any function in kernel, like snprintf, which will also
> collect strings but tread the buffer as ring buffer, such that I will
> not need to take care the overflow.

Look at include/linux/ring_buffer.h