WebMar 23, 2024 · In current C standards (C99, C11), one should type-pun via an union, rather than dereferencing a type-cast pointer: #include uint32_t float_bits (const float f) { union { uint32_t u; float f; } temp; temp.f = f; return temp.u; } Most current architectures use IEEE-754 binary32 format for float type, but not all. Web也就是说,字节具有未指定的值。它并没有说由这些字节表示的对象具有未指定的值。@stantario:不正确。字节可能不是陷阱,但它们形成的值可能是陷阱。在这种情况下,最合适的规则是C 2024 6.5.2.3 3,它说,对于成员访问(使用 或->
Is type-punning through a union unspecified in C99, and has it …
WebJava:在基元数组上使用类型punning?,java,buffer,primitive-types,bytebuffer,type-punning,Java,Buffer,Primitive Types,Bytebuffer,Type Punning,我需要能够将字节数组转换为其他基元类型数组或从其他基元类型数组转换为字节数组,但我需要的不是强制转换。 WebMar 5, 2024 · Thus, if the struct member is an array of character type, the constraints of N1570 6.5p7 would allow an lvalue of that form to access storage of any type. The maintainers of some compilers such as gcc, however, appear to view the laxity of the Standard there as a defect. This can be demonstrated via the code: closing remarks of tour guide
c++ - What is the strict aliasing rule? - Stack Overflow
WebThe behavior of type punning with union changed from C89 to C99. The behavior in C99 is the same as C11. As Wug noted in his answer, type punning is allowed in C99 / C11. An unspecified value that could be a trap is read when the union members are of different size. The footnote was added in C99 after Clive D.W. Feather Defect Report #257: WebDec 4, 2024 · The C standard allows for float and int objects to have different endianness, but this is uncommon in C implementations. As long as they have the same endianness, copying the bytes of an int into a float or vice-versa will have the expected result (of revealing the encoding of a float object in a natural way in the bits of an int ). Share Web我希望我可以只使用預處理器,但是輸入是在運行時來的。我嘗試了條件typedef,不起作用。 或條件聲明不起作用。 盡管我沒想到他們倆都不希望。 而且由於下面的所有代碼是完全相同的,所以我不想將其重寫兩次..每個結構一次。 有沒有辦法在C中做到這一點 或不同的方 … closing remarks means