Re: #pragma once

[Bryan Call <br...@gmail.com>]

I am +1 on using pragma once for ease of use.  However, there is no performance gain on compilation.  Modern compilers are already optimized for include guards.

-Bryan



> On Jul 31, 2017, at 7:52 AM, Jason Kenny <jk...@yahoo-inc.com.INVALID> wrote:
> 
> I want to bump this again. I started moving to this already. However James Peach was wanting to talk about this in dev for a different code review by someone else. I personally took the lack of discussion here a sign this was obvious ok, and a good thing to do as it is generally standard practice by most modern C++ people. However, this may not be so. So I want to bring the discussion on this again, for those that want to use inefficient #ifdef guards over the more modern #prgama once replacement.
> Jason
> 
> On Friday, July 7, 2017, 2:07:14 PM CDT, Jason Kenny <jk...@yahoo-inc.com> wrote:
> 
> Hi all,
> I would suggest we start using 
> #pragma once
> instead of the classic header guard of 
> #ifndef MYHEADER_H 
> #define MYHEADER_H
> ...#endif //MYHEADER_H
> The reason for this is that #pragma once:
> 1) is supported on all the compilers and all the platform combination we use for quite some time now. 2) it is easier to use than trying to deal with header guards, such as getting the name correct etc..3) the compiler already can optimize loading of headers better with pragma once, so compile times will only be faster and safer than before
> I suggest we allow the usage on new headers or in a code diff in which we clean up the code. We can use both at the same time without issue. This is a very safe and nice change to make
> Jason