Question

How can you name a macro and it's library

Answer 1

Answer:

• The macro is (putatively) more efficient, as it doesn't involve a function call. It can be optimised more easily, as it just involves a pointer offset lookup.

• The function call allows linking against the same library even if the program was compiled without the macro definition - if it was compiled with a different header, or just with a rogue declaration inside the source file. Should, for example, you have a compiler which has someone's "improved" version of ctype.h that didn't have the macro, the function would still exist at runtime for use.

If we look at the standard:

• Use of library functions. Any function declared in a header may be additionally implemented as a function-like macro defined in the header, so if a library function is declared explicitly when its header is included, one of the techniques shown below can be used to ensure the declaration is not affected by such a macro. Any macro definition of a function can be suppressed locally by enclosing the name of the function in parentheses, because the name is then not followed by the left parenthesis that indicates expansion of a macro function name. For the same syntactic reason, it is permitted to take the address of a library function even if it is also defined as a macro.

so here is your answer and please give a thanks.

and I am sure that it is 100% correct!!