Index: changes.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-5/changes.html,v retrieving revision 1.88 diff -u -r1.88 changes.html --- changes.html 10 Mar 2015 17:34:36 -0000 1.88 +++ changes.html 11 Mar 2015 18:06:52 -0000 @@ -189,6 +189,29 @@ of the standard directive #include and the extension #include_next respectively. +
  • A new built-in function to detect the existence of an attribute, + __has_attribute, has been added. The equivalent built-in + function __has_cpp_attribute was added to C++ to support + + Feature-testing recommendations for C++. + The function __has_attribute is added to all C-like + languages as an extension: +
    +int
    +#ifdef __has_attribute
    +#  if __has_attribute(__noinline__)
    +  __attribute__((__noinline__))
    +#  endif
    +#endif
    +foo(int x);
    +
    + If an attribute exists a nonzero constant integer is returned. + For standardized C++ attributes a date is returned, otherwise the + constant returned is 1. + The has_attribute macros will add underscores to an attribute name + if necessary to resolve the name. + For C++11 and onwards the attribute may be scoped. +
  • A new set of built-in functions for arithmetics with overflow checking has been added: __builtin_add_overflow, __builtin_sub_overflow and __builtin_mul_overflow