Hello Gregory, Do you recommend not to allow registration of a driver that does not have read method and make a requirement for the driver to provide at least dummy read?
Best regards, Petro On Fri, Apr 1, 2022, 9:48 PM Gregory Nutt <[email protected]> wrote: > > > One option, conforming standard, would be that you just always give > O_RDWR (same flags as what linux devices have), but then when calling > read/write you check if the pointer is non-null. If the driver doesn't > define read or write, those operations are allowed on the device, but act > as no-op. > > If you can't think of anything useful to do with read() or write(), > thenthis has been historically handled is by including a dummy read > method in the driver that just returns zero (EOF). For example, the > loop driver: > > > /**************************************************************************** > * Name: loop_read > > > ****************************************************************************/ > > static ssize_t loop_read(FAR struct file *filep, FAR char *buffer, > size_t len) > { > return 0; /* Return EOF */ > } > * > * >
