Walter Bright: > http://www.drdobbs.com/blog/archives/2010/08/c_compilation_s.html > I'll be doing a followup on why D compiles fast.
Thank you, the article is nice and I didn't know most of the things it contains. >the compiler is doomed to uselessly reprocess them when one file is #include'd >multiple times, even if it is protected by #ifndef pairs. (Kenneth Boyd tells >me that upon careful reading the Standard may allow a compiler to skip >reprocessing #include's protected by #ifndef pairs. I don't know which >compilers, if any, take advantage of this.)< Probably the latest GCC versions are able to do that. And then there is #pragma once too: http://en.wikipedia.org/wiki/Pragma_once >Just #include'ing the Standard results, on Ubuntu, in 74 files being read of >37,687 lines (not including any lines from multiple #include's of the same >file).< As benchmark on this Clang (the C/C++ compiler based on LLVM) uses a small program (~7500 lines of Object-C) that includes Cocoa/Cocoa.h, that is quite large: http://clang.llvm.org/performance.html Bye, bearophile
