Type punning

In <a href="/facts/Computer_science/lN3pEyPz">computer science</a>, a type punning is any programming technique that subverts or circumvents the <a href="/facts/Type_system/Tz0bAMS9">type system</a> of a <a href="/facts/Programming_language/cWTYbgWa">programming language</a> in order to achieve an effect that would be difficult or impossible to achieve within the bounds of the formal language.
In <a href="/facts/C_/Ky2No763">C</a> and <a href="/facts/C%252B%252B/Et0F2qn9">C++</a>, constructs such as <a href="/facts/Pointer_(computer_programming)/fPoNzy9b">pointer</a> <a href="/facts/Type_conversion/FuPD945T">type conversion</a> and <a href="/facts/Union_(computer_science)/GSV1DsyV">union</a> — C++ adds <a href="/facts/Reference_(computer_science)/1vm2Bph1">reference</a> type conversion and reinterpret_cast to this list — are provided in order to permit many kinds of type punning, although some kinds are not actually supported by the standard language.
In the <a href="/facts/Pascal_/b3yvp8bF">Pascal</a> programming language, the use of <a href="/facts/Record_(computer_science)/1fvSgenB">records</a> with <a href="/facts/Variant_type/VUo5FpRu">variants</a> may be used to treat a particular data type in more than one manner, or in a manner not normally permitted.

Type punning open-in-new

Type punning