assert.h File Reference

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Macros
#define	__has_feature(x)   0
#define	__has_extension   __has_feature
#define	STATIC_ASSERT_PRAGMA_START
#define	STATIC_ASSERT_PRAGMA_END
#define	STATIC_ASSERT(cond, msg)
	Assert at compile time if condition is not satisfied. More...
#define	STATIC_ASSERT_STATEMENT   STATIC_ASSERT_EXPR
#define	ASSERT_CONCAT_(a, b)   a##b
#define	ASSERT_CONCAT(a, b)   ASSERT_CONCAT_(a, b)
#define	STATIC_ASSERT_EXPR(e, m)   ((enum { ASSERT_CONCAT(assert_line_, __LINE__) = 1/(!!(e)) }) 0)
	Like STATIC_ASSERT, but can be used where expressions are used. More...
#define	STRICT_ADD(a, b, c, t)   do { *(c) = (t)(a + b); } while (0)
	Adds (a + b) and stores result in c. Aborts on overflow. More...
#define	STRICT_SUB(a, b, c, t)   do { *(c) = (t)(a - b); } while (0)
	Subtracts (a - b) and stores result in c. Aborts on overflow. More...

Macro Definition Documentation

#define __has_extension   __has_feature

#define __has_feature

(

x

)

0

#define ASSERT_CONCAT	(		a,
			b
	)		ASSERT_CONCAT_(a, b)

#define ASSERT_CONCAT_	(		a,
			b
	)		a##b

#define STATIC_ASSERT	(		cond,
			msg
	)

Value:

do { \
      STATIC_ASSERT_PRAGMA_START \
      STATIC_ASSERT_STATEMENT(cond, msg); \
      STATIC_ASSERT_PRAGMA_END \
    } while (0)

Assert at compile time if condition is not satisfied.

Should be put on its own line, followed by a semicolon.

Example:

STATIC_ASSERT(sizeof(void *) == 8, "Expected 64-bit mode");

Parameters

[in]	condition	Condition to check, should be an integer constant expression.
[in]	message	Message which will be given if check fails.

#define STATIC_ASSERT_EXPR	(		e,
			m
	)		((enum { ASSERT_CONCAT(assert_line_, __LINE__) = 1/(!!(e)) }) 0)

Like STATIC_ASSERT, but can be used where expressions are used.

STATIC_ASSERT_EXPR may be put in brace initializer lists. Error message given in this case is not very nice with the current implementation though and message argument is ignored.

#define STATIC_ASSERT_PRAGMA_END

#define STATIC_ASSERT_PRAGMA_START

#define STATIC_ASSERT_STATEMENT   STATIC_ASSERT_EXPR

#define STRICT_ADD	(		a,
			b,
			c,
			t
	)		do { *(c) = (t)(a + b); } while (0)

Adds (a + b) and stores result in c. Aborts on overflow.

Requires GCC 5+ and Clang 3.8+ https://clang.llvm.org/docs/LanguageExtensions.html https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html

Alternative for compilers without __builtin_xx_overflow ? https://stackoverflow.com/a/44830670/152142

Parameters

MAX	Maximum value of the narrowest type of operand. Not used if compiler supports __builtin_add_overflow.

#define STRICT_SUB	(		a,
			b,
			c,
			t
	)		do { *(c) = (t)(a - b); } while (0)

Subtracts (a - b) and stores result in c. Aborts on overflow.