Sure, that works for me ;-)
One more nitpick - on sub-section 4.2.7 there is an unmatched left
parenthesis before "and":
"POSIX supplies the pthread_key_create() function to create
a per-thread variable (and return the corresponding key, ..."
--Elad
On Mon, Jul 16, 2018 at 7:51 PM, Akira Yokosawa <akiyks@xxxxxxxxx> wrote:
> Hi Elad,
>
> On 2018/07/17 1:35, Elad Lahav wrote:
>> On Mon, Jul 16, 2018 at 11:42 AM, Akira Yokosawa <akiyks@xxxxxxxxx> wrote:
>>> First, two helpers are defined as follows:
>>>
>>> #define handle_error_en(en, msg) \
>>> do { errno = en; perror(msg); exit(EXIT_FAILURE); } while (0)
>>>
>>> #define handle_error(msg) \
>>> do { perror(msg); exit(EXIT_FAILURE); } while (0)
>>>
>>> Then, one of the call sites looks as follows:
>>>
>>> s = pthread_create(&tinfo[tnum].thread_id, &attr,
>>> &thread_start, &tinfo[tnum]);
>>> if (s != 0)
>>> handle_error_en(s, "pthread_create");
>>>
>>> If we employ this pattern, one of the hunks in your patch will look like:
>>>
>>> - if (pthread_mutex_lock(pmlp) != 0) {
>>> - perror("lock_reader:pthread_mutex_lock");
>>> - exit(-1);
>>> - }
>>> + if ((en = pthread_mutex_lock(pmlp)) != 0)
>>> + handle_error_en(en, "lock_reader:pthread_mutex_lock");
>>>
>>> Thoughts?
>>
>> You are, of course, free to do as you want with your book, but I would
>> advise against the proposal. Novice software developers will often
>> copy patterns from books, which means that the examples need to be
>> held to a higher standard. I do agree that error handling is not the
>> point of these examples, so you shouldn't spend too much time on it,
>> but at least at one point it should show the correct pattern. The rest
>> of the code can just have a "// Report error and exit" comment.
>> If you do want a helper, then a better solution would be:
>>
>> static inline void __attribute__((noreturn))
>> fatal(char const * const msg, int const err)
>> {
>> fprintf(stderr, "%s: %s\n", msg, strerror(err));
>> exit(EXIT_FAILURE);
>> }
>>
>> The name 'fatal' better conveys to the reader of the code the fact
>> that the call doesn't return. The snippet also demonstrates a more
>> modern approach to C code (use of inline functions, const, function
>> attributes).
>
> Thank you for your feedback!
>
> I agree with you that inline functions are better choice.
> You might also want to update the example in the man pages? ;-)
>
> Would function names of "fatal_en()" and "fatal()" as defined below
> work with you?
>
> static inline void __attribute__((noreturn))
> fatal_en(char const * const msg, int const err)
> {
> fprintf(stderr, "%s: %s\n", msg, strerror(err));
> exit(EXIT_FAILURE);
> }
>
> static inline void __attribute__((noreturn))
> fatal(char const * const msg)
> {
> perror(msg);
> exit(EXIT_FAILURE);
> }
>
> Thanks, Akira
>>
>> --Elad
>>
>
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