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Programmers should exercise caution if the second operand contains side effects because it may not be apparent whether the side effects actually occur.
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Noncompliant Code Example
In this noncompliant code example, the second operand of the logical OR operator invokes a function that results in side effects:
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| Code Block | ||||
|---|---|---|---|---|
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char *p = /* Initialize; may or may not be NULL */ char *q = NULL; if (p == NULL) { q = (char *) malloc(BUF_SIZE); p = q; } if (p == NULL) { /* Handle malloc() error */ return; } /* Perform some computation based on p */ free(q); q = NULL; |
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Failing to understand the short-circuit behavior of the logical OR or AND operator may cause unintended program behavior.
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
EXP02-C | Low | Unlikely | Medium | P2 | L3 |
Automated Detection
Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Astrée |
| logop-side-effect | Fully checked | ||||||
| Axivion Bauhaus Suite |
| CertC-EXP02 | Fully implemented | ||||||
| Compass/ROSE |
Could detect possible violations of this recommendation by reporting expressions with side effects, including function calls, that appear on the right-hand side of an | |||||||||
| Helix QAC |
| C3415 | |||||||
| Klocwork |
| MISRA.LOGIC.SIDEEFF | |||||||
| LDRA tool suite |
| 35 D | Fully implemented |
| Parasoft C/C++test |
| CERT_C-EXP02-a | The right-hand operand of a logical && or || operator shall not contain side effects | ||||||
| PC-lint Plus |
| 9007 | Fully supported | ||||||
| RuleChecker |
| logop-side-effect | Fully checked | ||||||
| SonarQube C/C++ Plugin |
| SideEffectInRightHandSideOfLogical |
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
| SEI CERT C++ |
| Coding Standard | VOID EXP02-CPP. Be aware of the short-circuit behavior of the logical AND and OR operators |
| MITRE CWE | CWE-768, Incorrect short circuit evaluation |
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