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Full Version: Rule 19.7 - Function-like macro
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I have a violation of MISRA 2004 Advisory Rule 19.7, Function-like macro defined: 'CONV'

#define F_MIN (-0.5)
#define F_MAX (0.5)
#define CONV(x) ((int32_t) ((x) < F_MAX ? ((x) >= F_MIN ? (x)*0x80000000U : 0xFFFF8000U) : 0x7fff0000U))

int32_t myVariable = CONV(0.25); /* the preprocessor replace macro with the value 0x20000000 */

How I declare the macro CONV(), which is not a function but really a preprocessor task, to be compliant to MISRA ?


Rule 19.7 is only intended to apply in situations where a function call would be permitted.

As an example, a function call is not permitted in a constant-expression. Therefore Rule 19.7 does not apply to the initialisers for objects that have static storage duration, e.g.

static int32 myVariable = CONV(0.25);   /* Rule 19.7 compliant - function not permitted here */