isprint core dump

[Ryan Johnson]

On 23/01/2012 4:39 PM, Eric Blake wrote:
> On 01/23/2012 02:34 PM, Nellis, Kenneth wrote:
>> From: Eric Blake
>>
>>> No, but it DOES come from POSIX:
>>> http://pubs.opengroup.org/onlinepubs/9699919799/functions/isprint.html
>>>
>>> And cygwin's behavior matches POSIX on this point; the bug is in your
>>> program, not cygwin.
>> Call me blown away by the level of support this function that
>> dumps core is getting, when it could act sanely (IMHO) with a
>> simple "if" statement! So much for defensive programming.
> If you want defensive programming, write the defense into your program -
> don't call functions with invalid arguments in the first place.  It
> costs time to process an if() statement that would be reached by every
> single caller, when 99.99% of the callers already comply with the
> standards.
That, and the if() would almost certainly mask the bug -- there's no 
value isprint() can return to signal an error, and if the sad state of 
errno and error code checking in general is any indication, the error 
condition would be ignored by 99.99% of buggy callers even if isprint() 
did signal it in some way.

I, for one, prefer my invalid code to trigger a nice, predictable seg 
fault immediately, rather than returning undefined results and/or 
causing malloc() to barf at some indeterminate point in the future.

Ryan


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