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Code that is executed but does not perform any action, or has an unintended effect, most likely results from a coding error and can cause unexpected behavior. Statements or expressions that have no effect should be identified and removed from code. Most modern compilers can warn about code that has no effect in many cases. (See MSC00-C. Compile cleanly at high warning levels.)

This recommendation is related to MSC07-C. Detect and remove dead code.

Noncompliant Code Example (Assignment)

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If the intent was to increment the value referred to by p, then parentheses can be used to ensure p is dereferenced and then incremented. (See EXP00-C. Use parentheses for precedence of operation.)

Code Block
bgColor#ccccff
langc
int *p;
/* ... */
(*p)++;

...

Tool

Version

Checker

Description

Coverity

Include Page
Coverity_V
Coverity_V

NO_EFFECT

Finds statements or expressions that do not accomplish anything or statements that perform an unintended action.

GCC

3.0

-Wunused-value and -Wunused-parameter

Options detect unused local variables or nonconstant static variables and unused function parameters, respectively.

Klocwork

Include Page
Klocwork_V
Klocwork_V

EFFECT

 

LDRA tool suite

Include Page
LDRA_V
LDRA_V

65 D
70 D
57 S

Fully implemented.

Splint

Include Page
Splint_V
Splint_V

 

 

PRQA QA·CQA-C
Include Page
PRQA_V
PRQA_V
 Partially implemented

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CERT C++ Secure Coding Standard: MSC12-CPP. Detect and remove code that has no effect

ISO/IEC TR 24772 "BRS Leveraging human experience," "BVQ Unspecified functionality," "KOA Likely incorrect expressions," and "XYQ Dead and deactivated code"

MISRA Rule 14.1 and Rule 14.2

Sources

[Coverity 2007]

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