From: Andy Shevchenko
> Sent: 04 September 2024 00:20
>
> Tue, Sep 03, 2024 at 04:01:21PM +0800, zhangjiao2 kirjoitti:
> > From: zhang jiao <zhangjiao2@xxxxxxxxxxxxxxxxxxxx>
> >
> > close fd when exit the program
>
> Please, mind English grammar and punctuation.
> Also this doesn't state what the problem is.
After all, when the program exits the kernel closes all the files.
> > if (ret == -1) {
> > fprintf(stderr, "Error adding watches[%d]: %s\n", i,
> > strerror(errno));
> > + close(fd);
>
> Since fd is not used in the messaging it's better to close it before printing
> anything. Ditto for other cases.
Unless close() decides to change errno...
>
> ...
>
> > if (ret != sizeof(event_data)) {
> > fprintf(stderr, "Failed to read event data\n");
> > + close(fd);
>
> > return -EIO;
>
> Side note: This will return garbage to the userspace. Should be
>
> return EIO;
If that is the return value from main() it is equally invalid.
Valid return values are 0..255 but 128..255 are likely to be
interpreted as 'killed by a signal'.
So really you only get 0..127.
Mostly used as 0 => success and 1 => failure.
David
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