Subject: Re: [boost] numeric_cast
From: Antony Polukhin (antoshkka_at_[hidden])
Date: 2011-06-24 06:46:51
2011/6/24 Tom Tan <ttan_at_[hidden]>:
> It seems to me the outer #ifdef works for MSVC as well. What's the extra
> benefit of embedding an inner #pragma once in this case?
In case there is no pragma in header, compiler will open header file
again when it is included and will parse it till include guards.
If there is a pragma, compiler will not open and parse the file again.
So pragma can reduce compilation time.