attributes.h File Reference

Function and variable attributes. More...

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Macros
#define	HAS_ATTRIBUTE(TOK)
#define	UsageOptional   __attribute__( ( __unused__ ) )
	Stops compiler warnings when the function/variable is unused.
#define	PrintfLike(FORMAT_STRING, FIRST_VAR_ARG)
	Tells the compiler which varargs correspond to a format string.
#define	ScanfLike(FORMAT_STRING, FIRST_VAR_ARG)
	Tells the compiler which varargs correspond to a format string.
#define	UseResult   __attribute__( ( __warn_unused_result__ ) )
	Function's return value must be used.
#define	Cold   __attribute__( ( __cold__ ) )
#define	Const   __attribute__( ( __const__ ) )
#define	BeforeMain   __attribute__( ( constructor ) )
	Function runs before entering main
#define	NoReturn   __attribute__( ( noreturn ) )
	Function always exits.
#define	Deprecated   __attribute__( ( deprecated ) )
	Function is deprecated and shouldn't be used.
#define	Constructor   UseResult
#define	Private   static
#define	LibraryDefined   static UsageOptional
#define	Mathematical   Const
#define	NonNullParams(...)

Detailed Description

Function and variable attributes.

Whether the compiler supports attributes (GCC/Clang) or not, this header creates platform-independent macros for certain attributes a function or variable may have.

Some combinations may (definitely will) be missing; this isn't an exhaustive list. (Though all macros are safe to use, no matter the compiler)

Macro Definition Documentation

BeforeMain

#define BeforeMain   __attribute__( ( constructor ) )

Function runs before entering main

Cold

#define Cold   __attribute__( ( __cold__ ) )

Const

#define Const   __attribute__( ( __const__ ) )

Functions return value only depends on its parameters

Constructor

#define Constructor   UseResult

Function allocates memory for an object. Not using function's return value results in a memory leak (or worse).

Deprecated

#define Deprecated   __attribute__( ( deprecated ) )

Function is deprecated and shouldn't be used.

HAS_ATTRIBUTE

#define HAS_ATTRIBUTE

(

TOK

)

Value:

__has_attribute( TOK )

Evaluates as true if the compiler (clang/GCC) supports the attribute

LibraryDefined

#define LibraryDefined   static UsageOptional

Function or variable is defined in a header file

Mathematical

#define Mathematical   Const

Function has no effect except for the return value. Function's return value only depends on its parameters.

NonNullParams

#define NonNullParams

(

...

)

Value:

__attribute( ( nonnull( __VA_ARGS__ ) ) )

Must not be NULL

NoReturn

#define NoReturn   __attribute__( ( noreturn ) )

Function always exits.

PrintfLike

#define PrintfLike	(		FORMAT_STRING,
			FIRST_VAR_ARG )

Value:

    __attribute__( ( __format__( __printf__, FORMAT_STRING, FIRST_VAR_ARG ) ) )

Tells the compiler which varargs correspond to a format string.

Private

#define Private   static

Function or variable is not visible outside the current file

ScanfLike

#define ScanfLike	(		FORMAT_STRING,
			FIRST_VAR_ARG )

Value:

    __attribute__( ( __format__( __scanf__, FORMAT_STRING, FIRST_VAR_ARG ) ) )

Tells the compiler which varargs correspond to a format string.

UsageOptional

#define UsageOptional   __attribute__( ( __unused__ ) )

Stops compiler warnings when the function/variable is unused.

UseResult

#define UseResult   __attribute__( ( __warn_unused_result__ ) )

Function's return value must be used.