eal/windows: resolve conversion and truncation warnings

  * Initialize const int NS_PER_SEC with an integer literal instead of
  double thereby avoiding implicit conversion from double to int.

* Cast the result of the expression assigned to timspec.tv_nsec to long.
  Windows builds generate integer truncation warning for this assignment
  since the result of the expression was 8 bytes (LONGLONG) but
  on Windows targets is 4 bytes. The value produced for the expression
  should safely fit in the long.

Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
---
 lib/eal/windows/include/rte_os_shim.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
  

2023-08-02 13:48 (UTC-0700), Tyler Retzlaff:
> * Initialize const int NS_PER_SEC with an integer literal instead of
>   double thereby avoiding implicit conversion from double to int.
> 
> * Cast the result of the expression assigned to timspec.tv_nsec to long.

Typo: "timespec".

>   Windows builds generate integer truncation warning for this assignment
>   since the result of the expression was 8 bytes (LONGLONG) but
>   on Windows targets is 4 bytes.

Probably "but **tv_nsec** on Windows targets is 4 bytes".

>   The value produced for the expression should safely fit in the long.
> 
> Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
> ---
>  lib/eal/windows/include/rte_os_shim.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
  

On Thu, Aug 03, 2023 at 01:29:00AM +0300, Dmitry Kozlyuk wrote:
> 2023-08-02 13:48 (UTC-0700), Tyler Retzlaff:
> > * Initialize const int NS_PER_SEC with an integer literal instead of
> >   double thereby avoiding implicit conversion from double to int.
> > 
> > * Cast the result of the expression assigned to timspec.tv_nsec to long.
> 
> Typo: "timespec".

oops 

> 
> >   Windows builds generate integer truncation warning for this assignment
> >   since the result of the expression was 8 bytes (LONGLONG) but
> >   on Windows targets is 4 bytes.
> 
> Probably "but **tv_nsec** on Windows targets is 4 bytes".

thanks i'll update the wording.

one thing that confuses me a little and this change won't break how the
code already works (just makes the cast redundant) is that for mingw
sizeof(long) is being reported as 8 bytes.

this is in spec relative to the C standard but it does leave me somewhat
concerned if struct timespec as defined in the windows headers crosses
an abi boundary.

have you ever noticed this? any thoughts on it?

> 
> >   The value produced for the expression should safely fit in the long.
> > 
> > Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
> > ---
> >  lib/eal/windows/include/rte_os_shim.h | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>

thanks!
  

2023-08-02 15:41 (UTC-0700), Tyler Retzlaff:
> one thing that confuses me a little and this change won't break how the
> code already works (just makes the cast redundant) is that for mingw
> sizeof(long) is being reported as 8 bytes.
> 
> this is in spec relative to the C standard but it does leave me somewhat
> concerned if struct timespec as defined in the windows headers crosses
> an abi boundary.

MinGW-w64 shows sizeof(long) == 4 in my tests, both native and cross build.
Which MinGW setup reports sizeof(long) == 8 on Windows target?
  

On Thu, Aug 03, 2023 at 02:44:45AM +0300, Dmitry Kozlyuk wrote:
> 2023-08-02 15:41 (UTC-0700), Tyler Retzlaff:
> > one thing that confuses me a little and this change won't break how the
> > code already works (just makes the cast redundant) is that for mingw
> > sizeof(long) is being reported as 8 bytes.
> > 
> > this is in spec relative to the C standard but it does leave me somewhat
> > concerned if struct timespec as defined in the windows headers crosses
> > an abi boundary.
> 
> MinGW-w64 shows sizeof(long) == 4 in my tests, both native and cross build.
> Which MinGW setup reports sizeof(long) == 8 on Windows target?

it must have been a dream, i just checked and i get the results you do.

ignore me i'm tired, thanks for checking though.