Doug Gregor, who works on Clang at Apple (via Hacker News): The C preprocessor has long been a source of problems for programmers and tools alike. Programmers must contend with widespread macro pollution and include-ordering problems due to ill-behaved headers. Developers habitually employ various preprocessor workarounds, such as LONG_MACRO_PREFIXES, include guards, and the occasional #undef … Continue reading C and Objective-C Modules Proposal