. You can explicitly perform the following conversions: A pointer to any integral type large enough to hold it A value of integral or enumeration type to a pointer Web reinterpret_cast . This rule bans (T)expression best when used to accomplish an unsafe cast. Huge difference. The operator used for this purpose is known as the cast operator. Answers and comments should really reflect the latest available Standard unless otherwise specified IMHO. Whats the membrane surrounding abdominal viscera? What happens if you mix the two cast? @jaskmar Regarding your Explanation part, how is it possible, that the result of static_cast will produce same results regardless of endianness? Notes. Heres a contrived example where a vendor provides an API for storing and retrieving arbitrary global data: To use this API, the programmer must cast their data to VendorGlobalUserData and back again. Many web browsers, such as Internet Explorer 9, include a download manager. An explicit specialization of a function template is inline only if it is declared with the inline specifier (or defined as deleted), it doesn't matter if the primary template is inline.. WebObjects with trivial default constructors can be created by using reinterpret_cast on any suitably aligned storage, e.g. @HeretoLearn, is it possible to add the relevant code pieces from the *.c and *.cpp file? (y == x) as selected by overload resolution.Defaulting the relational operators can be useful in order c-v certified method const and riskyFor e.g:- // non cv_qualified int first; char *2nd; // cv-qualified const int third; unstable char * fourth; https://stackoverflow.com/questions/27527642/what-does-cv-qualified-mean/27527673#27527673. C++4: static_cast, reinterpret_cast, const_cast dynamic_cast. It treats the binary representation of the float as an integer, shifts it right and subtracts it from a constant, thereby halving and negating the exponent. The reinterpret_cast operator cannot be used to cast away const; use const_cast for that purpose. It's in C99, in , as an optional type.Many C++03 compilers do provide that file. NOTE: In both cases you should save the casted value in a variable before cast! The reinterpret_cast operator should not be used to ; 5 How is difficulty calculated? When to use std::forward to forward arguments? When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used - C++, Should I use static_cast or reinterpret_cast when casting a void* to whatever - C++. ; A non-owning type (i.e. Should I use static_cast or reinterpret_cast when casting a void* to whatever. size_t is an unsigned integer data type which can assign only 0 and greater than 0 integer values. Rather, reinterpret_cast has a number of meanings, for all of which holds that the mapping performed by reinterpret_cast is implementation-defined. [5.2.10.3]. The consequence of a reinterpret_cast can't safely be used for the rest instead of being solid again to its original sort. There are more explicit methods which allow us to describe the intention of our cast. Neither expression guarantees when the actual incremented value is stored back to x, it is only guaranteed that it happens before the next sequence point. static_cast will not prevent this from happening. This does not actually answer the question of "when to use reinterpret_cast". (char)a will make 'a' function as a char. From en.cppreference.com/w/cpp/language/reinterpret_cast: "Unlike static_cast, but like const_cast, the reinterpret_cast expression does not compile to any CPU instructions. So when you convert int* to float* with this keyword, the new value (after pointer dereferecing) has nothing to do with the old value in mathematical meaning. Using reinterpret_cast to check inheritance at compile time. For the case you describe, and pretty much any case where you might consider reinterpret_cast, you can use static_cast or some other alternative instead. @DanielKamilKozar who says about switching it? JSONde nlohmann JSON JSON You can use tips to consistent knowledge as function parameters to prevent the function from enhancing a parameter handed thru a pointer. WebThis may seem like pedantry (mainly because it is :) ) but in C++, x++ is a rvalue with the value of x before increment, x++ is an lvalue with the value of x after an increment. A valid identifier must begin with a non-digit character (Latin letter, underscore, or Unicode character of class XID_Start) and may contain non-digit characters, digits, and Unicode characters of class XID_Continue It compiles fine on the newest gcc (8.3.0) but the standard says it is illegal. So you have to check the byte order. dynamic_cast In C++ | How To Use dynamic_cast In C++? If delete is applied to one of the pointers, then the object's memory is returned to the free store. No, neither a reinterpret_cast nor its C-style cast equivalent perform any checking, so they cannot by themselves cause an exception. static_cast This is used for the commonplace/bizarre kind conversion. The compiler can then check that the cast is between related types, reporting a compile-time error if this isn't the case. I am currently writing a program that needs to manipulate a tree structure (abstract syntax tree). In the tree a node owns its children as unique_ptr and looks like: unique_ptr , While changing the tree it should be possible to replace a node in the tree. For that purpose i store a self pointer to the owning unique_ptr in each node. unique_ptr self A replacement action would look like:, Now the problem is to set the self pointer after constructing a node.self To achieve that i am using reinterpret_cast :reinterpret_cast , My Question is now: is it save using reinterpret_cast in this way, as long i don't break the inheritance hierarchy like mentioned above? reinterpret_cast inheritance , Don't reinterpret_cast .reinterpret_cast You can use std::unique_ptr 's constructors to transfer ownership polymorphically.std::unique_ptr . When and how is it decided to either use a cast or not? A very lightweight abstraction of a contiguous sequence of values of type T somewhere in memory. If you know what the compilers you are going to use do with reinterpret_cast you can use it, but to say that it is portable would be lying. Let's imagine the example: you have to read binary 32bit number from file, and you know it is big endian. For a conversion of void* to int* you can only use static_cast (or the equivalent C-style cast). Theres a misconception that using reinterpret_cast would be a better match because it meanscompletely ignore type safety and just cast from A to B. This is what static_cast stands for. Not if you use it properly. int someint; char4 v4 = as_char4 (someint)) is implementation-defined. Your code has to be generic and works properly on big endian (e.g. WebGenerally, a download manager enables downloading of large files or multiples files in one session. Is there a technical reason to use > (<) instead of != when incrementing by 1 in a 'for' loop? Type punning is the possibility of a programming language intentionally subvert the type system to treat a type as a different type. Implicit Type Conversion is also known as 'automatic type conversion'. b/c it requires ifstream or ofstream objects. That is, in the following, a, b and c all point to the same address: reinterpret_cast only guarantees that if you cast a pointer to a different type, and then reinterpret_cast it back to the original type, you get the original value. To typecast something, simply put the type of variable you want the actual variable to act as inside parentheses in front of the actual variable. move(d)std::unique_ptr<D>std::unique_ptr<D>&& It is safe, and in fact, preferable in generic code, to use deduction to forwarding reference, for (auto && var : sequence). This also works for doubles and long doubles. WebGPU CUDAStreamCUDA When the UpdateHook callback is invoked, one of the parameters is reinterpret_cast ed back to the reference counted class Database^ database = reinterpret_cast(data); database->OnChange(action,dbName,tableName,rowId); Now we are wondering how the reference The short answer: Hence, in theory a reinterpret_cast could crash your program. I thought that reinterpret_cast<> guaranteed the same bit pattern. OK, true, but I don't care about a version from 13 years ago, and nor should most coders if (as is likely) they can avoid it. This is your one-stop encyclopedia that has numerous frequently asked questions answered. For example, when using a C-style cast, as in. It is purely a compile-time directive which This macro could help: You could use reinterprete_cast to check inheritance at compile time.Look here: 6 What is the current difficulty? There are a few circumstances where you might want to use a dynamic_cast instead of a static_cast, but these mostly involve casts in a class hierarchy and (only rarely) directly concern void*. reinterpret_cast: Casts anything which has the same size, for example, int to FancyClass* on x86. OPTIMIZE: I think reinterpret_cast would be optimized in many compilers, while the c-casting is made by pointerarithmetic (the value must be copied to the memory, cause pointers couldn't point to cpu- registers). It is well-known on compile time so you can write constexpr function: You can write a function to achieve this: Explanation: the binary representation of x in memory could be 0000'0000'0000'0001 (big) or 0000'0001'0000'0000 (little endian). When you use C++ casts, you sign a contract You should use it in cases like converting float to int, char to int, etc. some ARM) and little endian (e.g. Android does not use Java bytecodes or It just treats a set of bits in the memory like if it had another type. C++ Weekly - Ep 185 - Stop Using reinterpret_cast! 'after processing the current A value of type pointer to object converted to pointer to cv void and back to the original pointer type will have its original value. Explanation Unlike static_cast, but like const_cast, the reinterpret_cast in this program. unique_ptr * unique_ptr *? - How to convert unique_ptr* to unique_ptr*? In C++, a pointer to an object can be converted to void * without any casts. (in practice it will typically contain the same address as a and c, but that's not specified in the standard, and it may not be true on machines with more complex memory systems.). All the data types of the variables are upgraded to the data type of the variable with the largest data type. reinterpret_cast, on the other hand, is a casting operator designed to do conversions that are fundamentally not safe or not portable. When should I use the new keyword in C++? reinterpret_cast is a type of casting operator used in C++. It only stop you when you remember it's unspecified. So you have to check the byte order. One more interesting thing that I keep running into (irrelevant to this) is the lack of a defined typecast between c10::BFloat16 and __nv_bfloat16.c10::Half casts to __half without a hitch, but in the case of bfloat16 I've had to just manually reinterpret cast to avoid the issue.. As far as atomicadds for bfloat go, I'm getting roughly 100x the latency I get You declare the existence of global variables in a header, so that each source file that includes the header knows about it, but you only need to define it once in one of your source files.. To clarify, using extern int x; tells the compiler that an object of type int called x exists somewhere.It's not the If you know what the compilers you are going to use do with reinterpret_cast you can use it, but to say that it is portable would be lying. The other two is sometimes confusing. This will paintings, but this style of cast is not recommended in C++. std::move Is there a good reason to favor one over the other? Though from what I have been reading it appears static is better as the cast can happen at compile time? Hence, in theory a reinterpret_cast could crash your program. Your email address will not be published. You cannot cast away a const or volatile qualification. (which is not the same as a valid pointer to another type). Which generally means that it's the identical size as a pointer. SQL Server 2012 via native C++ (no ATL) preferred access method from Windows, algorithm to add values of two ranges and place them into a third one. So when you convert int* to float* with this keyword, the new value (after pointer dereferecing) has nothing to do with the old value in mathematical meaning. I tried to conclude and wrote a simple safe cast using templates. Though it says to use reinterpret_cast to convert from one pointer type to another? The C++ compiler is not as kind. unsigned int u = reinterpret_cast(&i); One use of reinterpret_cast is if you want to apply bitwise operations to (IEEE 754) floats. lol, I suspect that reinterpret_crash might indeed crash your program. One example of this was the Fast Inverse Square-Root trick: https://en.wikipedia.org/wiki/Fast_inverse_square_root#Overview_of_the_code. WebReinterpret cast will always return a pointer. ;). It is done by the compiler on its own, without any external trigger from the user. It gives a java style of easier coding, whrein, data can be passed by reference without using complexity of pointer. std:: insert iterator for unordered sets (or maps). The reinterpret_cast operator should not be used to convert between pointers to different classes that are in the same class hierarchy; use a static or dynamic cast for that purpose. To clarify: what the author means here by ". unique_ptr unique_ptr - Convert unique_ptr to unique_ptr, unique_ptr unique_ptr unique_ptr - Downcasting unique_ptr to unique_ptr with unique_ptr in Derived, std::unique_ptr std::unique_ptr - Converting std::unique_ptr to std::unique_ptr, std :: unique_ptr std :: unique_ptr - Can no longer convert between std::unique_ptr to std::unique_ptr. This occurs frequently in vendor APIs over which the programmer has no control. How would you create a standalone widget from this widget tree? After converting back to a float, it's subjected to a Newton-Raphson iteration to make this approximation more exact: This was originally written in C, so uses C casts, but the analogous C++ cast is the reinterpret_cast. It treats the binary representation of the float as an integer, shifts it right and subtracts it from a constant, thereby halving and negating the exponent. ICU is an example of a library that does this in several places. The result of a Rely on the implicit conversion if possible or use static_cast. Their endianness remains the same and won't magically change. some ARM) and little endian (e.g. using static_cast to convert float to string c++, convert integer types to pointer types and vice versa. "Bi-endian" CPUs have their endianness set early by initialisation code, and running actual code is only possible if the binary's endianness equals the CPU's endianness. How to check if widget is visible using FlutterDriver. The static_cast correctly returns the address of the embedded A object, and the pointer created by static_cast correctly gives the value of the data field. If you use static-casting, it will always be 0000'0001, no matter what endianness is being used. WebUse static objects where possible, then when needed create a pointer to that instance. Create a pointer variable with the name ptr , that issues to a string variable, via using the asterisk sign * ( string* ptr ). One use of reinterpret_cast is to convert a pointer to an unsigned integer (when pointers and unsigned integers are the same size): int i; This is done regardless of whether the member is a type, data member, function, or enumerator, and regardless static_cast wont work, one must use reinterpret_cast: Below is a contrived implementation of the sample API: I tried to conclude and wrote a simple safe cast using templates. DXGI_SWAP_EFFECT_DISCARD Value: 0 Use this flag to specify the bit-block transfer (bitblt) model and to specify that DXGI discard the contents of the back buffer after you call IDXGISwapChain1::Present1. Here is a variant of Avi Ginsburg's program which clearly illustrates the property of reinterpret_cast mentioned by Chris Luengo, flodin, and cmdLP: that the compiler treats the pointed-to memory location as if it were an object of the new type: It can be seen that the B object is built in memory as B-specific data first, followed by the embedded A object. The expression consists of a dereference applied to a cast. When should i use streams vs just accessing the cloud firestore once in flutter? You could use reinterprete_cast to check inheritance at compile time. If we subsequently delete the second pointer, then the free store may be corrupted. const is the syntax representation of size_t , but without const you can run the program. WebOne use of reinterpret_cast is to convert a pointer to an unsigned integer (when pointers and unsigned integers are the same size): int i; unsigned int u = Should I use static_cast or reinterpret_cast when casting a void* to whatever. This occurs frequently in vendor APIs over which the programmer has no control. Although the reinterpret_cast itself may well be unspecified behaviour, attempting to get entry to the parameters once you could have finished the forged is undefined behaviour. BRIEF: it means that the same memory is used as a different type. If T is an aggregate class and the braced-init-list has a single element of the same or derived type (possibly cv-qualified), the object is initialized from that element (by copy-initialization for copy-list-initialization, or by direct-initialization for direct-list-initialization). But this is often surprisingly the best reason to use it. It is well-known on compile time so you can write constexpr function: You can write a function to achieve this: Explanation: the binary representation of x in memory could be 0000'0000'0000'0001 (big) or 0000'0001'0000'0000 (little endian). Well, the reinterpret_cast itself would probably not crash, but it could return some bogus the result that, when you try to use it, could cause a crash. But in the particular case of casting from void* to T* the mapping is completely well-defined by the standard; namely, to assign a type to a typeless pointer without changing its address. WebA reinterpret_cast is a cast that represents an unsafe conversion that might reinterpret the bits of one value as the bits of another value. Is MethodChannel buffering messages until the other side is "connected"? WebSander's answer. I think it can improve the exposition of the question. This static_cast<>() may also be spotted anyplace inside of a C++ code. The index is then truncated through a standard C-style forged to the go back kind of the function. ; 8 Can the network difficulty go down? In fact C++03 deprecates use of For example, casting an int* to a double* is What is the use of const_cast in C++? Using reinterpret_cast to do this with pointer conversions completely bypasses the compile-time safety check. reinterpret_cast does not happen at run time. Not always an option. It interfaces a file-based streambuffer (std::basic_filebuf) with the high-level interface of (std::basic_iostream).A typical implementation of std::basic_fstream holds only one non-derived data member: an instance of std:: On the other hand, it is clear that, for embedded users and specialized compilers/flags/environments, it could be useful to some degree. C* is now not on the path so static_cast will produce compile-time error. You must use it in cases like converting glide to int, char to int, and so on. 4 base base_collectionderived::base derived_collection::base_collection base_collection derived_collection Lets imagine the example: you have to read binary 32bit number from file, and you know it is big endian. Here's a contrived example where a vendor provides an API for storing and retrieving arbitrary global data: To use this API, the programmer must cast their data to VendorGlobalUserData and back again. static_cast won't work, one must use reinterpret_cast: Below is a contrived implementation of the sample API: The short answer: reinterpret_cast unique_ptr - unique_ptr with reinterpret_cast, will the structure get freed correctly? First you have some data in a specific type like int here: Then you want to access the same variable as an other type like float: You can also use reinterpret_cast to convert a float* to an int* or vice-versa, which is platform-specific because the particular representations of floats and ints aren't guaranteed to have anything in common with one another. WebUse reinterpret_cast to do unsafe conversions of pointer types to and from integer and other pointer types, including void*. WebRsidence officielle des rois de France, le chteau de Versailles et ses jardins comptent parmi les plus illustres monuments du patrimoine mondial et constituent la plus complte ralisation de lart franais du XVIIe sicle. C ++unique_ptr unique_ptr [] - c++ Cast a vector of unique_ptr to unique_ptr where derived is a template [duplicate]. Here is a better reference (with links to the standard): There is never a reason to check endianness at runtime. C++Server Side ProgrammingProgramming. Hence, in theory a reinterpret_cast could crash your program. Too much to remember. Here is a variant of Avi Ginsburgs program which clearly illustrates the property of reinterpret_cast mentioned by Chris Luengo, flodin, and cmdLP: that the compiler treats the pointed-to memory location as if it were an object of the new type: It can be seen that the B object is built in memory as B-specific data first, followed by the embedded A object. When to use volatile with multi threading? Welcome to FAQ Blog! The general idea I get is this is unportable and should be avoided. You likely obtained that void* with implicit conversion, so you should use static_cast because it is closest to the implicit conversion. The C++ standard guarantees the following: static_casting a pointer to and from void* preserves the address. x86) systems. The worst ever invented. whenComplete() method not working as expected - Flutter Async, iOS app crashes when opening image gallery using image_picker. Base TBase (The 1000 is put there to skip over a specific amount of chars before the specified break point, in this case, the \n newline character.) YUV420RGBAlibyuv. Required fields are marked *. C++ has two types of conversions: Implicit conversion: Conversions are performed automatically by the compiler without the programmer's intervention. unique_ptr unique_ptr - Why is automatic upcasting from unique_ptr to unique_ptr failing in this example? If you know what the compilers you are going to use do with reinterpret_cast you can use it, but to say that it is portable would be lying. How it works if you change the number of components (e.g. WebOne use of reinterpret_cast is to convert a pointer to an unsigned integer (when pointers and unsigned integers are the same size): int i; unsigned int u = reinterpret_cast (&i); TRPh 167 score:11 One use of reinterpret_cast is if you want to apply bitwise operations to (IEEE 754) floats. With reinterpret_cast you can cast a pointer type to any other pointer type, for example Youd need a static_cast to get the original pointer back. For the case you describe, and pretty much any case where you might consider reinterpret_cast, you can use static_cast or some other alternative instead. Summary Only use reinterpret_castwhen you are 1000000%sure what type you have in front of you. To answer the other part of your question, yes, reinterpret_cast is implementation-defined. For example, in the spoof checker API, you deal with pointers of type. Use unsafe code to reinterpret pointers. So in the following: a and c contain the same value, but the value of b is unspecified. When do I use a dot, arrow, or double colon to refer to members of a class in C++? You can decide between. const is the syntax representation of size_t , but with out const you'll run the program. Several shared_ptr objects may own the same object. It stops you doing silly things with it. One typical way to do type punning in C++ is to read the member of a union with a different type from the one with which it was written. No delete call needed. It is true that "it means that the same memory is used as a different type" but it is restricted to specific pair of types. But its not true the other way round. Acorn 23513 Example: It is true that reinterpret_cast is not portable because of one reason - byte order (endianness). This can be useful https://www.codetg.com/article/7r1QnR43bm3ZogBJ.html std :: make_uniquestd :: make_unique That is, in the following, a, b and c all point to the same address: reinterpret_cast only guarantees that if you cast a pointer to a different type, and then reinterpret_cast it back to the original type, you get the original value. You can't reinterpret_cast one struct to another because of strict, Note that although casting something to char or (u)int8_t is allowed, casting the other way around is UB (f.eks. This is the cast the C++ compiler uses internally for implicit casts also. But the value of B is unspecified, and yes, if you rely on that, bad things could happen. ControllerSender classBasicSender function MidiControllers::AddSender object map map const_cast is one of the kind casting operators. Typecasting is making a variable of one type, such as an int, act like another type, a char, for one single operation. Though from what I have been reading it appears static is better as the cast can happen at compile time? After reinterpret-casting the byte under p pointer could be respectively 0000'0000 or 0000'0001. It is well-known on compile time so you can write constexpr function: You can write a function to achieve this: Explanation: the binary representation of x in memory could be 0000'0000'0000'0001 (big) or 0000'0001'0000'0000 (little endian). @LokiAstari I think unspecified does not stop you from doing silly things. 0 Likes Share usachovandrii This can cast related type classes. reinterpret_cast, on the other hand, is a casting operator designed to do conversions that are fundamentally not safe or not portable. @anon Apparently you've never worked with POSIX threads before then. 2.4 reinterpret_ cast() (:) : int i = 0; char j='c'; int *p1=reinterpret_cast(&i); char *p2=reinterpret_cast(&j); //int p3=reinterpret_casti; //, The result is then bit-shifted and XORed with itself to supply a novel index (unique to a high stage of chance). For casting to and from void*, static_cast should be preferred. 1) const_cast can be used to change non-const class members inside a const member function. So for your use case, it seems fairly clear that the standardization committee intended for you to use static_cast. const_cast is used to cast away the constness of variables. = can be defaulted. WebC++static_cast,const_cast,dynamic_castreinterpret_cast You'd need a static_cast to get the original pointer back. WebThe Java language is designed to enforce type safety. The reinterpret_cast operator can't be used to cast away const; use const_cast for that purpose. The meaning of reinterpret_cast is not defined by the C++ standard. And then another user claimed it cast a, @curiousguy Not true according to the standard. Jul 30, 2011 at 3:20pm. For the case you describe, and pretty much any case where you might consider reinterpret_cast, you can use static_cast or some other alternative instead. static_cast is the cast of choice when there is a natural, intuitive conversion between two types that isn't necessarily guaranteed to work at runtime. It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions. One case when reinterpret_cast is necessary is when interfacing with opaque data types. This is exclusively to be used in inheritence when you cast from base class to derived class. ; 3 What is the formula for difficulty? I know that a "deleting the same memory twice" error can happen when two pointers address the same dynamically allocated object. The Strict aliasing rule permits us to avoid redundant machine code in circumstances in which it must be protected to assume that two tips do not point to the identical reminiscence block (see additionally the restrict key phrase). reinterpret_cast is a sort of casting operator used in C++. When you convert for example int(12) to unsigned float (12.0f) your processor needs to invoke some calculations as both numbers has different bit representation. How to check if widget is visible using FlutterDriver. I tried it on my compiler, and somehow, it refused to compile, This may be a late question, but why doesn't the vendor API use, hmm, true about reinterpret-casting to/from. OPTIMIZE: I think reinterpret_cast would be optimized in many compilers, while the c-casting is made by pointerarithmetic (the value must be copied to the memory, cause pointers couldnt point to cpu- registers). Generally, a download manager enables downloading of large files or multiples files in one session. dynamic_cast This cast is used for handling polymorphism. The C and C++ standards require any program (for a hosted C or C++ implementation) to have a function called main, which serves as the program's startup function.The main function is called after zero-initialization of non-local static variables, and possibly but not necessarily (!, C++11 3.6.2/4) this call happens The reinterpret_cast operator should now not be used to convert between tips that could different categories which might be in the same class hierarchy; use a static or dynamic solid for that purpose. Cryptoauthlib - An anonymous union can only have non-static data members - segmentation fault. On the one hand, Konrad makes an excellent point about the spec definition for reinterpret_cast, although in practice it probably does the same thing. A reinterpret_cast cannot convert nullptr_t to any pointer type. I do think casting from, The general rule is that static_cast cannot cast unrelated types. For example, you can't conveniently search for casts using an ordinary editor or word processor. Unlike C, the C++ compiler allows implicit conversions TO a void * type, but to convert FROM a void * type requires an explicit cast. When you convert for example int(12) to unsigned float (12.0f) your processor needs to invoke some calculations as both numbers has different bit representation. The C++ standard guarantees the following: static_casting a pointer to and from void* preserves the address. Now, we have got a complete detailed explanation and answer for everyone, who is interested! The clang compiler refuses to compile it (which is correct). What is the difference between bdiff and pdiff? First you have some data in a specific type like int here: Then you want to access the same variable as an other type like float: a "reference-type" rather than a "value type"): It never allocates nor deallocates anything and does not keep When to use inline function and when not to use it? This means that when you use it to convert from, say, an int* to But reinterpret_cast won't. x86) systems. static_cast This is used for the normal/ordinary type conversion. Use static_cast: it is the narrowest cast that exactly describes what conversion is made here. This near-invisibility of C-style casts is especially unfortunate because they are so potentially damaging. WebIn current C++, you can't use reinterpret_cast like in that code. Web reinterpret_cast (v) v 2 reinterpret_cast This is a question our experts keep getting from time to time. const_cast (expr) The const_cast operator is used to explicitly override const and/or unstable in a forged. The static_cast is used for the standard/extraordinary kind conversion. For example, you can use Your code has to be generic and works properly on big endian (e.g. ; 9 What is the minimum For an overview of the interfaces that you can use to create Direct2D content, see the Direct2D API overview. It is optionally defined in C++11 and later requirements. Obviously, since both constructs are about as unsafe as it gets, dereferencing the result pointer ap could cause undefined behavior. std::shared_ptr is a smart pointer that retains shared ownership of an object through a pointer. When should you use constexpr capability in C++11? As for which one is preferred by the spec, neither is overly mentioned as "the right one to use" (or at least, I don't remember one of them being mentioned this way.) If you don't know what reinterpret_cast stands for, don't use it. If you will need it in the future, you will know. So in the following: a and c contain the same value, but the value of b is unspecified. CC BY-SA 4.0:yoyou2525@163.com. (C++03 5.3.10). If it is set to 0, then OpenGL will assume that the vertex data is tightly packed. @MarcusJ: restricting your values to powers of 2 permits you to use your enums as bit-flags. Should I avoid typedef, try to use primitive names and cast when possible? First thing, at the time the question was asked, uintptr_t was not in C++. Nice example! choice between win32 APIs and .NET framework, Is it possible to check if a function with a string as its name exists?(C++). The standard forged like (int)x is C genre typecasting where static_cast(x) is used in C++. You can't reinterpret_cast in the case you give because reinterpret_cast takes only either a int to convert to a pointer, or the reverse, and follo They are both compile-time statements. 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