Hi Marcel,

No, because I don't believe it will work. I think the underlying problem 
is the difference between streams and files. When a process creates a 
stream (e.g. socket), the kernel creates a buffer and can start 
receiving data from an external source. This buffer can be accessed 
non-blocking from the process and the kernel can signal to the process 
when data was received. If the process opens a file, the kernel doesn't 
know what the process will do next (read or write, offset of the file, 
transfer size). So the kernel doesn't read/write any bytes unless the 
process sends a command to the kernel. And the POSIX read/write 
functions on files are always blocking. That leaves us with using 
multi-threading (POSIX AIO) or other linux specific syscalls (libaio, 
preadv2).

Regards
Simon

On 9/20/21 9:20 AM, Marcel Holtmann wrote:
> Hi Simon,
> 
>> I'm looking now into libaio. POSIX AIO is implemented in libc with user threads, while libaio uses linux native syscalls. Maybe I can also get rid of signal usage. IMHO non-blocking file access / async IO is quite important for embedded applications and it would be nice to have this feature in ell.
> 
> have you looked into using l_idle for providing async read/write callbacks that way. I have the feeling that AIO is total overkill for embedded applications.
> 
> Regards
> 
> Marcel
>