On Fri, Dec 14, 2007 at 04:28:58PM -0000, John Maddock wrote:
Jens Seidel wrote:
PS2: I still miss an explanation from you why you use both internal and external inclusion guards: boost/math/complex/asinh.hpp contains:
#ifndef BOOST_MATH_COMPLEX_DETAILS_INCLUDED # include <boost/math/complex/details.hpp> #endif
and boost/math/complex/details.hpp:
#ifndef BOOST_MATH_COMPLEX_DETAILS_INCLUDED #define BOOST_MATH_COMPLEX_DETAILS_INCLUDED
Is this just old code or was it necessary because of the asinh/asin typo and you did so for other files as well?
I suggest to remove all outer include guards (also in other files).
Why? It makes no difference, except to improve performance for compilers that don't implement the include-guard detection trick that gcc uses.
Heh? What trick? To ensure that an include file is not included twice one normally defines a unique preprocessor macro at the beginning of the header file and skips processing if it was previously defined. Doesn't every Boost header does this? Do you consider using #define a trick? I just want to mention that #include <boost/math/complex/details.hpp> is easier to read than #ifndef BOOST_MATH_COMPLEX_DETAILS_INCLUDED # include <boost/math/complex/details.hpp> #endif It is also more secure because you increase the chance to make a typo in the macro which could be hard to track down. You're right that it could be a little bit faster but I have never seen it somewhere (including Boost). I was just curious ... Jens