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In this noncompliant code example, an assignment expression is the outermost expression in an if statement.:

Code Block
bgColor#FFcccc
langc
if (a = b) {
  /* ... */
}

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When the assignment of b to a is not intended, this conditional block is now executed when a is equal to b.:

Code Block
bgColor#ccccff
langc
if (a == b) {
  /* ... */
}

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In this noncompliant example, the expression x = y is used as the controlling expression of the while statement.:

Code Block
bgColor#FFcccc
langc
 do { /* ... */ } while ( foo(), x = y ) ;

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When the assignment of y to x is not intended, this conditional block is now executed when x is equal to y.:

Code Block
bgColor#ccccff
langc
do { /* ... */ } while ( foo(), x == y ) ; 

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In this noncompliant example, the expression p = q is used as the controlling expression of the while statement.:

Code Block
bgColor#FFcccc
langc
 do { /* ... */ } while ( x = y, p = q ) ;

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This is a compliant example because the expression x = y is not used as the controlling expression of the while statement.:

Code Block
bgColor#ccccff
langc
do { /* ... */ } while ( x = y, p == q ) ; 

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In this compliant example, the expression x = y  is itself a parameter to a comparison operation:

Code Block
bgColor#ccccff
langc
if ( ( x = y )  != 0  ) { /* ... */ } 

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In this compliant example, the expression  x = y is a single primary expression.:

Code Block
bgColor#ccccff
langc
if ( ( x = y ) ) { /* ... */ } 

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In this compliant example, the expression x = y is used in a function argument.:

 

Code Block
bgColor#ccccff
langc
if ( foo( x = y ) ) { /* ... */ } 

This is a noncompliant example because && is not a comparison or relational operator and the entire expression is not primary

.

:

Code Block
bgColor#FFcccc
langc
if ( ( v = w ) && flag ) { /* ... */ }

When the assignment of v to w is not intended, this conditional block is now executed when v is equal to w.:

Code Block
bgColor#ccccff
langc
if ( ( v == w ) && flag ) { /* ... */ }; 

When the assignment is intended, the following is an alternative compliant solution:

Code Block
bgColor#ccccff
langc
if ( ( (v = w) != 0 ) && flag ) { /* ... */ };

Risk Assessment

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Tool

Version

Checker

Description

Compass/ROSE

 

 

Could detect violations of this recommendation by identifying any assignment expression as the top-level expression in an if or while statement.

ECLAIR

Include Page
ECLAIR_V
ECLAIR_V

exprctxt

Fully implemented.

GCC

Include Page
GCC_V
GCC_V

 

Can detect violations of this recommendation when the -Wall flag is used.

Klocwork

Include Page
Klocwork_V
Klocwork_V

ASSIGCOND.GEN
ASSIGCOND.CALL

 

LDRA tool suite

Include Page
LDRA_V
LDRA_V

9 S

 

PRQA QA-C
Include Page
PRQA_V
PRQA_V
3314Partially implemented.

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

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