Re: [PATCH 1/8] tools lib bpf: add error functions

[Wangnan (F)]

On 2016/10/19 6:52, Joe Stringer wrote:
> On 16 October 2016 at 14:18, Eric Leblond <eric@xxxxxxxxx> wrote:
> > The include of err.h is not explicitely needed in exported
> > functions and it was causing include conflict with some existing
> > code due to redefining some macros.
> >
> > To fix this, let's have error handling functions provided by the
> > library. Furthermore this will allow user to have an homogeneous
> > API.
> >
> > Signed-off-by: Eric Leblond <eric@xxxxxxxxx>
> Does it need to return the error like this or should we just fix up
> the bpf_object__open() API to return errors in a simpler form?
>
> There's already libbpf_set_print(...) for outputting errors, is it
> reasonable to just change the library to return NULLs in error cases
> instead?

Returning error code to caller so caller knows what happen.
Other subsystems in perf also do this.

Perf hides libbpf's error output (make it silent unless -v),
so it needs a way for receiving libbpf's error code.

I think this patch is good, decouple libbpf.h and kernel headers.

Thank you.