Audio. Graphviz. Bytecode. Pcc. Gil. ERB. NestedVM. An Introduction to GCC. Inline Functions In C. Introduction GNU C (and some other compilers) had inline functions long before standard C introduced them (in the 1999 standard); this page summarizes the rules they use, and makes some suggestions as to how to actually use inline functions.
The point of making a function inline is to hint to the compiler that it is worth making some form of extra effort to call the function faster than it would otherwise - generally by substituting the code of the function into its caller. As well as eliminating the need for a call and return sequence, it might allow the compiler to perform certain optimizations between the bodies of both functions. Sometimes it is necessary for the compiler to emit a stand-alone copy of the object code for a function even though it is an inline function - for instance if it is necessary to take the address of the function, or if it can't be inlined in some particular context, or (perhaps) if optimization has been turned off.
It wastes space. C99 inline rules. Virtual inheritance overhead in g++ By now every C++ engineer worth her salt knows that virtual inheritance is not free. It has object code, runtime (both CPU and memory), as well as compilation time and memory overheads (for an in-depth discussion on how virtual inheritance is implemented in C++ compilers see “Inside the C++ Object Model” by Stanley Lippman). In this post I would like to consider the object code as well as compilation time and memory overheads since in modern C++ implementations these are normally sacrificed for the runtime speed and can present major surprises. Unlike existing studies on this subject, I won’t bore you with “academic” metrics such as per class or per virtual function overhead or synthetic tests. Such metrics and tests have two main problems: they don’t give a feeling of the overhead experienced by real-world applications and they don’t factor in the extra code necessary to account for the lack of functionality otherwise provided by virtual inheritance.