<P> C++ is often considered to be a superset of C, but this is not strictly true . Most C code can easily be made to compile correctly in C++, but there are a few differences that cause some valid C code to be invalid or behave differently in C++ . For example, C allows implicit conversion from void * to other pointer types, but C++ does not (for type safety reasons). Also, C++ defines many new keywords, such as new and class, which may be used as identifiers (for example, variable names) in a C program . </P> <P> Some incompatibilities have been removed by the 1999 revision of the C standard (C99), which now supports C++ features such as line comments (/ /), and declarations mixed with code . On the other hand, C99 introduced a number of new features that C++ did not support, were incompatible or redundant in C++, such as variable - length arrays, native complex - number types (however, the std:: complex class in the C++ standard library provides similar functionality, although not code - compatible), designated initializers, compound literals, and the restrict keyword . Some of the C99 - introduced features were included in the subsequent version of the C++ standard, C + + 11 (out of those which were not redundant). However, the C + + 11 standard introduces new incompatibilities, such as disallowing assignment of a string literal to a character pointer, which remains valid C . </P> <P> To intermix C and C++ code, any function declaration or definition that is to be called from / used both in C and C++ must be declared with C linkage by placing it within an extern "C" (/ *...* /) block . Such a function may not rely on features depending on name mangling (i.e., function overloading). </P> <P> Despite its widespread adoption, many programmers have criticized the C++ language, including Linus Torvalds, Richard Stallman, and Ken Thompson . Issues include a lack of reflection or garbage collection, slow compilation times, perceived feature creep, and verbose error messages, particularly from template metaprogramming . </P>

Which of the following is not a standard exception built in c plus plus