16f6c0aecf
Inline adoc files when they are included exactly once. Also fix language tags because this inlining gives us better information on what language the code is written in.
40 lines
1.3 KiB
Plaintext
40 lines
1.3 KiB
Plaintext
== Why is this an issue?
|
|
|
|
Because ``++reinterpret_cast++`` ignores the type system, it is capable of performing dangerous conversions between unrelated types which can lead to undefined behavior.
|
|
|
|
|
|
This rule reports an issue for two problematic uses of ``++reinterpret_cast++``:
|
|
|
|
* when it is used to make the compiler believe that an object in memory is from a different type from its real type (for instance, casting a ``++long*++`` to ``++double*++``, because accessing a ``++long++`` as if it was a ``++double++`` is undefined behavior (even if ``++sizeof(long) == sizeof(double)++``),
|
|
* when it is used to cast between different levels of a complex inheritance hierarchy (a ``++static_cast++`` would apply pointer offsets to take into account multiple inheritance, for instance, but ``++reinterpret_cast++`` does not)
|
|
|
|
|
|
=== Noncompliant code example
|
|
|
|
[source,cpp]
|
|
----
|
|
class X {};
|
|
class Y : virtual X {};
|
|
|
|
void test() {
|
|
long l;
|
|
auto a = reinterpret_cast<double&>(l); // Noncompliant: undefined behavior
|
|
|
|
Y* y;
|
|
auto x = reinterpret_cast<X*>(y); // Noncompliant
|
|
}
|
|
----
|
|
|
|
ifdef::env-github,rspecator-view[]
|
|
|
|
'''
|
|
== Implementation Specification
|
|
(visible only on this page)
|
|
|
|
=== Message
|
|
|
|
reinterpret_cast from "XXX" to "YYY" has undefined behavior
|
|
|
|
|
|
endif::env-github,rspecator-view[]
|