On Thu, Jul 20, 2023 at 3:02 PM Fotis Panagiotopoulos <f.j.pa...@gmail.com> wrote:
> Hello, > > I am using fprintf() to output some data to a file. This file is located on > an SD card. > > As I realised, fprintf() never returns an error. > > I tried to completely remove the SD card from the system, and fprintf > happily succeeds, > returning the number of bytes that it would have written, if the write was > successful. > > By checking the call trace, I see that the problem lies within > vsprintf_internal(). > It calls stream_putc() but no error checking is done there. > > Shouldn't this be considered a bug? > I haven't studied the code, so I may be off here, but... If fprintf() return code indicates success to my application, my expectation is that the data has been written. However it might be a little more complicated than that: what if fprintf() successfully *buffered* the data and the fs layer is waiting for an opportunity to write it? In this scenario fprintf would return to the application before writing completes. Then, it would be sensible for fprintf to indicate success (of the buffering) even though data wasn't actually stored on flash yet. Maybe a separate call to sync the fs is needed? Having said all that, stream_putc should probably do error checking and propagate errors. Cheers Nathan
