22b4470f2a
Update all links to C++ Core Guidelines to `e49158a`.
Refresh done using the following script and some manual edits:
db76e34e74/personal/fred-tingaud/rspec/refresh-cppcoreguidelines.py
When re-using this script, be mindful that:
- it does not cover `shared_content`
- it does not properly escape inline code in links (e.g., "[=]" or "`mutex`es")
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Co-authored-by: Marco Borgeaud <marco.borgeaud@sonarsource.com>
70 lines
1.7 KiB
Plaintext
70 lines
1.7 KiB
Plaintext
== Why is this an issue?
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Attempting to make a comparison between pointers using >, >=, < or +<=+ will produce undefined behavior if the two pointers point to different arrays.
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Additionally, directly comparing two arrays for equality or inequality has been deprecated in {cpp}.
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However, equality or inequality between an array and a pointer is still valid
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=== Noncompliant code example
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[source,cpp]
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----
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void f1 ( )
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{
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int a1[ 10 ];
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int a2[ 10 ];
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int * p1 = a1;
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if ( p1 < a2 ) // Non-compliant, p1 and a2 point to different arrays.
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{
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}
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if ( p1 - a2 > 0 ) // Non-compliant, p1 and a2 point to different arrays.
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{
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}
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if ( a1 == a2) // Non-compliant (in C++). Comparing different array for equality is deprecated
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{
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}
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}
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----
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=== Compliant solution
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[source,cpp]
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----
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void f1 ( )
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{
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int a1[ 10 ];
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int * p1 = a1;
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if ( p1 < a1 ) // Compliant, p1 and a1 point to the same array.
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{
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}
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if ( p1 - a1 > 0 ) // Compliant, p1 and a1 point to the same array.
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{
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}
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if ( p1 == a2 ) // Compliant, comparing a pointer and an array for equality is valid
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{
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}
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}
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----
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== Resources
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* MISRA C:2004, 17.3 - >, >=, <, +<=+ shall not be applied to pointer types except where they point to the same array.
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* MISRA {cpp}:2008, 5-0-18 - >, >=, <, +<=+ shall not be applied to objects of pointer type, except where they point to the same array.
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* {cpp} Core Guidelines - https://github.com/isocpp/CppCoreGuidelines/blob/e49158a/CppCoreGuidelines.md#es62-dont-compare-pointers-into-different-arrays[ES.62: Don't compare pointers into different arrays]
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ifdef::env-github,rspecator-view[]
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'''
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== Comments And Links
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(visible only on this page)
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=== is related to: S939
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=== is related to: S940
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endif::env-github,rspecator-view[]
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