cdefs.h File Reference

Various common macros used throughout the codebase. More...

#include <sys/cdefs.h>

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Macros
#define	__noreturn   __attribute__((__noreturn__))
	Identify a function that will never return.
#define	__pure   __attribute__((__const__))
	Identify a function that has no side effects other than its return, and only uses its arguments for any work.
#define	__unused   __attribute__((__unused__))
	Identify a function or variable that may be unused.
#define	__used   __attribute__((used))
	Prevent a symbol from being removed from the binary.
#define	__weak   __attribute__((weak))
	Identify a function or variable that may be overridden by another symbol.
#define	__packed   __attribute__((packed))
	Force a structure, enum, or other type to be packed as small as possible.
#define	__dead2   __noreturn /* BSD compat */
	Alias for __noreturn.
#define	__pure2   __pure /* ditto */
	Alias for __pure.
#define	__likely(exp)   __builtin_expect(!!(exp), 1)
	Directive to inform the compiler the condition is in the likely path.
#define	__unlikely(exp)   __builtin_expect(!!(exp), 0)
	Directive to inform the compiler the condition is in the unlikely path.
#define	__deprecated   __attribute__((deprecated))
	Mark something as deprecated.
#define	__printflike(fmtarg, firstvararg)    __attribute__((__format__ (__printf__, fmtarg, firstvararg)))
	Identify a function as accepting formatting like printf().
#define	__scanflike(fmtarg, firstvararg)    __attribute__((__format__ (__scanf__, fmtarg, firstvararg)))
	Identify a function as accepting formatting like scanf().
#define	__fallthrough   /* Fall through */
#define	__always_inline   inline __attribute__((__always_inline__))
	Ask the compiler to always inline a given function.
#define	__no_inline   __attribute__((__noinline__))
	Ask the compiler to never inline a given function.
#define	__RESTRICT
#define	__extension__
#define	inline   __inline__
#define	__build_assert(cond)    do { (void) sizeof(char [1 - 2*!(cond)]); } while(0)
	Assert a build-time dependency.
#define	__build_assert_or_zero(cond)    (sizeof(char [1 - 2*!(cond)]) - 1)
	Assert a build-time dependency.
#define	__array_size(arr)   (sizeof(arr) / sizeof((arr)[0]) + _array_size_chk(arr))
	Get the number of elements in a visible array.
#define	_array_size_chk(arr)   0

Detailed Description

Various common macros used throughout the codebase.

This file contains various convenience macros. Mostly compiler attribute directives, as well as other language defines, and useful language extensions.

Author

Megan Potter

Lawrence Sebald

Falco Girgis