On Fri, 8 May 2015, Manuel López-Ibáñez wrote: > "At present, the first parameter in a function prototype must have > some type specifier that is not an attribute specifier; this resolves > an ambiguity in the interpretation of void f(int (__attribute__((foo)) > x))" > https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute-Syntax > > But I don't understand the example given in the docs.
This means that this example is interpreted as void f(int __attribute__((foo)) x); and not void f(int (*)(int __attribute__((foo)) x)); (with implicit int and adjustment of a parameter declared with function type to have pointer to function type), which would be a valid parse if you only consider the syntax productions without the above disambiguation. Cf C11 6.7.6.3#11 "If, in a parameter declaration, an identifier can be treated either as a typedef name or as a parameter name, it shall be taken as a typedef name." (disambiguating cases such as "void f(int (T))" where T is a typedef name). And some other cases in C90 that became irrelevant in C99 with the removal of implicit int. -- Joseph S. Myers jos...@codesourcery.com
