Cygwin /usr/bin/stat returns "Birth: -", which value in FILE_BASIC_INFORMATION.CreationTime causes that?

[Brian Inglis]

On 2024-04-04 19:08, Martin Wege via Cygwin wrote:
> On Fri, Apr 5, 2024 at 2:55 AM Brian Inglis via Cygwin
> <cygwin@cygwin.com> wrote:
>>
>> On 2024-04-04 18:05, Martin Wege via Cygwin wrote:
>>> I have problems with debugging, so a quick help would be appreciated,
>>> as I cannot figure this out after several hours of digging.
>>>
>>> Cygwin /usr/bin/stat returns "Birth: -" for some files. Which value
>>> must the CreationTime member of FILE_BASIC_INFORMATION have to cause
>>> /usr/bin/stat ti return "-"? 0, -1, or something else?
>>
>> https://git.savannah.gnu.org/cgit/coreutils.git/tree/src/stat.c#n1618
>>
>> => tv_nsec < 0
>>
>> https://cygwin.com/git?p=newlib-cygwin.git;a=blob;f=winsup/cygwin/fhandler/disk_file.cc#l414
>>
>> https://cygwin.com/git/?p=newlib-cygwin.git;a=blob;f=winsup/cygwin/times.cc#l283
> 
> Thank you
> 
> But how can tv_nsec become negative (tv_nsec < 0)? That can only
> happen if BasicInformation.CreationTime.QuadPart is negative, right?

Caller or application can set 0 to mean keep/return current value, caller or 
driver can set -1 to mean don't update/return current value:

https://learn.microsoft.com/en-us/windows-hardware/drivers/ddi/wdm/ns-wdm-_file_basic_information#remarks

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry