[previous] MISRA-C:2004  Rule  14.1:  (Required) [next] There shall be no unreachable code.
This rule refers to code which cannot under any circumstances be reached, and which can be identified as such at compile time. Code that can be reached but may never be executed is excluded from the rule (e.g. defensive programming code).

A portion of code is unreachable if there is no control flow path from the relevant entry point to that code. For example, unlabelled code following an unconditional control transfer is unreachable: 

switch ( event )
{
case E_wakeup:
    do_wakeup();
    break;         /* unconditional control transfer   */
    do_more();     /* Not compliant - unreachable code */
    /* ... */
default:
    /* ... */
    break;
}

A whole function will be unreachable if there is no means by which it can be called.

Code that is excluded by pre-processor directives is not present following pre-processing, and is therefore not subject to this rule.

QAC messages that encompass this guideline:

0594 Negative 'case' label expression is incompatible with unsigned controlling expression in 'switch' statement.
1460 'Switch' label value, %s, not contained in enum type.
1503 The function '%1s' is defined but is not used within this project.
2008 Code statements precede the first label in this 'switch' construct.
2742 This 'if' controlling expression is a constant expression and its value is 'false'.
2744 This 'while' or 'for' loop controlling expression is a constant expression and its value is 'false'. The loop will not be entered.
2880 This code is unreachable.
2882 This 'switch' statement will bypass the initialization of local variables.
3219 Static function '%s()' is not used within this translation unit.


(c) The Motor Industry Research Association, 2004
QA C Source Code Analyser 8.1.2
MISRA-C:2004 Compliance Module 3.2
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