cdefs.h File Reference

Potentially useful definitions for C Programs. More...

#include <sys/cdefs.h>

Go to the source code of this file.

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	__dead2   __noreturn /* BSD compat */
	Alias for __noreturn. For BSD compatibility.
#define	__pure2   __pure /* ditto */
	Alias for __pure. Fore BSD compatibility.
#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().

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Detailed Description

Potentially useful definitions for C Programs.

This file contains definitions of various attribute directives in shorter forms for use in programs (to aid in optimization, mainly).

Author:

Dan Potter

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Macro Definition Documentation

#define __dead2   __noreturn /* BSD compat */

Alias for __noreturn. For BSD compatibility.

#define __noreturn   __attribute__((__noreturn__))

Identify a function that will never return.

#define __printflike	(		fmtarg,
			firstvararg
	)		__attribute__((__format__ (__printf__, fmtarg, firstvararg)))

Identify a function as accepting formatting like printf().

Using this macro allows GCC to typecheck calls to printf-like functions, which can aid in finding mistakes.

Parameters:

fmtarg	The argument number (1-based) of the format string.
firstvararg	The argument number of the first vararg (the ...).

#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 __pure2   __pure /* ditto */

Alias for __pure. Fore BSD compatibility.

#define __scanflike	(		fmtarg,
			firstvararg
	)		__attribute__((__format__ (__scanf__, fmtarg, firstvararg)))

Identify a function as accepting formatting like scanf().

Using this macro allows GCC to typecheck calls to scanf-like functions, which can aid in finding mistakes.

Parameters:

fmtarg	The argument number (1-based) of the format string.
firstvararg	The argument number of the first vararg (the ...).

#define __unused   __attribute__((__unused__))

Identify a function or variable that may be unused.