MISRA C:2012  Rule-14.3:  (Required)			Controlling expressions shall not be invariant

Amplification:

This rule applies to:

• Controlling expressions of if, while, for, do ... while and switch statements;
• The first operand of the ?: operator.

Exception:

1. Invariants that are used to create infinite loops are permitted.
2. A do-while loop with an essentially Boolean controlling expression that evaluates to 0 is permitted.

Example Code:

#pragma PRQA_MESSAGES_OFF 2982

#include "misra.h"
#include "m3cmex.h"

extern int16_t rule_1403( void )
{
    int16_t loop = 1;

    while (loop != 0)                                           /* 2990           */
    {
        if (s16a > 10)
        {
            break;
        }
    }                                                           /* 2467           */

    if ((s16a < 10) || (s16a > 0))                              /* 2991 2995 2996 */
    {
    }

    if ((s16a < 10) && (s16a > 20))                             /* 2992      2996 */
    {
    }

    do
    {
        ++u16a;
    } while (u16a < 0u);                                        /* 2993      2996 */

    return 1;
}

QAC messages that encompass this guideline:

2990	The value of this loop controlling expression is always 'true'.
2991	The value of this 'if' controlling expression is always 'true'.
2992	The value of this 'if' controlling expression is always 'false'.
2993	The value of this 'do - while' loop controlling expression is always 'false'. The loop will only be executed once.
2994	The value of this 'while' or 'for' loop controlling expression is always 'false'. The loop will not be entered.

(c) The Motor Industry Research Association, 2012

QA C Source Code Analyser 8.1.2 MISRA C:2012 Compliance Module 1.0 © 2013 Programming Research www.programmingresearch.com

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