On 27/06/11 21:42, Edward Diener wrote:
On 6/27/2011 12:59 PM, Stephan T. Lavavej wrote:
[Mateusz Loskot]
Is location of #pragma relevant? Meaning, having #pragma nested in #ifndef include guard vs. placing it in outer scope, makes difference or not?
VC doesn't care where the #pragma once is, but as I recall, other compilers care where the #ifndef is - they prefer it to be on the outside of everything else, except comments.
I doubt if any compiler cares where the #ifndef ( or #if !defined ) is. It is just C++ after all and the preprocessor should handle it according to the C++ standard. It has just become conventional to write:
#ifndef SOME_MACRO #define SOME_MACRO
// header code
#endif
My question was if related to #pragma once specifically and previous comments on why to use it together with include guards. So, I asked if Visual C++ handles these two in the same or different manner: 1) #ifndef SOME_MACRO #define SOME_MACRO #pragma once // header code #endif 2) #pragma once #ifndef SOME_MACRO #define SOME_MACRO // header code #endif Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org Member of ACCU, http://accu.org