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In this example, p2 is assigned the value returned by bar(), but that value is never used. Note this example assumes that foo() and bar() return valid pointers. (see See guideline DCL30-C. Declare objects with appropriate storage durations.).

int *p1, *p2;
p1 = foo();
p2 = bar();

if (baz()) {
  return p1;
}
else {
  p2 = p1;
}
return p2;

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Automated Detection

The LDRA tool suite Version 7.6.0 can detect violations of this recommendation.

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Tool	Version	Checker	Description
Section LDRA tool suite	Include Page c:LDRA_V c:LDRA_V
Section Coverity Prevent	Include Page c:Coverity_V c:Coverity_V	Section UNUSED_VALUE	Section finds variables that are assigned pointer values returned from a function call but never used

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Section Klocwork	Include Page c:Klocwork_V c:Klocwork_V		Section can detect violations of this rule with a number of checkers

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Related Vulnerabilities

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

Other Languages

Related Guidelines

This rule appears in the C++ Secure Coding Standard as : MSC13-CPP. Detect and remove unused values.

Bibliography

\[[Coverity 072007|AA. Bibliography#Coverity 07]\]
\[[ISO/IEC PDTR 24772|AA. Bibliography#ISO/IEC PDTR 24772]\] "BRS Leveraging human experience," "KOA Likely incorrect expressions," "XYQ Dead and Deactivated Code," and "XYR Unused Variable"

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