Re: [PATCH v2 3/7] Create helper functions to deal with handles on interactive gatttool

Hi Johan,

On Wed, Feb 23, 2011 at 12:09 AM, Johan Hedberg [off-list ref] wrote:

Hi Sheldon,

On Tue, Feb 22, 2011, Sheldon Demario wrote:

quoted

+     *dst = strtoll(src, &e, 16);
+     if (errno != 0 || *e != '\0') {
+             return -1;
      }

Firstly, you've got a coding style issue here: no {} for one-line
scopes. Secondly, are you sure that this is the right way to check for
strtoll failure? If there was some earlier libc function that failed
errno might be set to != 0 even if strtoll succeeds, right? Or are all
errno using libc functions guaranteed to set errno to 0 on success?
Reading the man-page of strtoll it seems you should be checking for
LLONG_MIN and LLONG_MAX return values.

Looking at "man errno", it is not guaranteed for errno to be set to
zero on success, therefore the recommended way is to set it to zero
prior to calling the function to be checked.

The NOTES section from "man strtoll" recommends using errno when
checking for errors:

"Since strtol() can legitimately return 0, LONG_MAX, or LONG_MIN
(LLONG_MAX or LLONG_MIN for strtoll()) on both success and failure,
the calling program  should  set errno to 0 before the call, and then
determine if an error occurred by checking whether errno has a
non-zero value after the call."

So I think the only missing bit here it to set errno to zero prior to
calling strtoll()

Regards,
-- 
Anderson Lizardo
Instituto Nokia de Tecnologia - INdT
Manaus - Brazil