typeof(3) [netbsd man page]

TYPEOF(3)						   BSD Library Functions Manual 						 TYPEOF(3)

NAME

     typeof -- GNU extension for type of an expression

SYNOPSIS

     type
     typeof(expression);

DESCRIPTION

     The typeof() construct can be used to obtain the type of an expression.  The syntax is comparable to that of sizeof(), but semantically
     typeof() operates like a type name defined with typedef.

EXAMPLES

     The following is a typical example of a type-generic macro:

	   #define MAX(a, b) ({ 	   
		   typeof(a) _a = (a);	   
		   typeof(b) _b = (b);	   
		   _a > _b ? _a : _b;	   
	   })

SEE ALSO

     gcc(1), __alignof__(3), attribute(3), offsetof(3)

CAVEATS

     The typeof() construct is a non-standard, compiler-specific extension.

BSD
								 December 19, 2010							       BSD

__BUILTIN_OBJECT_SIZE(3)				   BSD Library Functions Manual 				  __BUILTIN_OBJECT_SIZE(3)

NAME

     __builtin_object_size -- return the size of the given object

SYNOPSIS

     size_t
     __builtin_object_size(void *ptr, int type);

DESCRIPTION

     The __builtin_object_size() function is a gcc(1) built-in function that returns the size of the ptr object if known at compile time and the
     object does not have any side effects.

RETURN VALUES

     If the size of the object is not known or it has side effects the __builtin_object_size() function returns:

	   (size_t)-1  for type 0 and 1.

	   (size_t)0   for type 2 and 3.

     If the size of the object is known, then the __builtin_object_size() function returns the maximum size of all the objects that the compiler
     knows that they can be pointed to by ptr when type & 2 == 0, and the minimum size when type & 2 != 0.

SEE ALSO

     gcc(1), __builtin_return_address(3), attribute(3), ssp(3)

HISTORY

     The __builtin_object_size() appeared in GCC 4.1.

CAVEATS

     This is a non-standard, compiler-specific extension.

BSD
								 December 19, 2010							       BSD