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Unlike passed-by-value arguments and pointers, pointed-to values are a concern. A function may modify a value referenced by a pointer argument, leading to a side effect that persists even after the function exits. Modification of the pointed-to value is not diagnosed by the compiler, which assumes this behavior was intended.
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The const
-qualification of the second argument, s2
, eliminates the spurious warning in the initial invocation but maintains the valid warning on the final invocation in which a const
-qualified object is passed as the first argument (which can change). Finally, the middle strcat()
invocation is now valid because c_str3
is a valid destination string and may be safely modified.
Risk Assessment
Not declaring Failing to declare an unchanging value const
prohibits the function from working with values already cast as const
. This problem can be sidestepped by type casting away the const
, but doing so violates EXP05-C. Do not cast away a const qualification.
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
---|---|---|---|---|---|
DCL13-C | Low | Unlikely | Low | P3 | L3 |
Automated Detection
Tool | Version | Checker | Description | ||||||
---|---|---|---|---|---|---|---|---|---|
Astrée |
| parameter-missing-const | Fully checked | ||||||
Axivion Bauhaus Suite |
| CertC-DCL13 | |||||||
CodeSonar |
| LANG.TYPE.CBCONST | Pointed-to Type Could Be const | ||||||
Compass/ROSE |
Can detect violations of this recommendation while checking for violations of recommendation DCL00-C. Const-qualify immutable objects | |||||||||
| CC2.DCL13 | Fully implemented | |||||||
Helix QAC |
| C0431, C3673, C3677 | |||||||
Klocwork |
| MISRA.PPARAM.NEEDS.CONST | |||||||
LDRA tool suite |
|
120 D | Fully implemented |
3673
0431(C)
Parasoft C/C++test |
| CERT_C-DCL13-a | A pointer parameter in a function prototype should be declared as pointer to const if the pointer is not used to modify the addressed object | ||||||
PC-lint Plus |
| 111, 818 | Fully supported | ||||||
Polyspace Bug Finder |
| CERT C: Rec. DCL13-C | Checks for pointer to non-const qualified function parameter (rec. fully covered) | ||||||
RuleChecker |
| parameter-missing-const | Fully checked |
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
SEI CERT C++ |
Coding Standard | VOID DCL13-CPP. Declare function parameters that are pointers to values not changed by the function as const |
ISO/IEC TR 24772:2013 | Passing Parameters and Return Values [CSJ] |
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MISRA C:2012 | Rule 8.13 (advisory) |
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