Asking for help, clarification, or responding to other answers. Making statements based on opinion; back them up with references or personal experience.
How to correctly type cast (void*)? - social.msdn.microsoft.com You are getting warnings due to casting a void* to a type of a different size. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ What is the point of Thrower's Bandolier? Most answers just try to extract 32 useless bits out of the argument. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? In this case, casting the pointer back to an integer is meaningless, because . reinterpret_cast is a type of casting operator used in C++. Put your define inside a bracket: #define M_TABLE_SIZE (64*1024) Now, you can do: static const void* M_OFFSET = (void*) M_TABLE_SIZE; without a problem. "clang" "-Ilib\libopenvswitch.a.p" "-Ilib" "-I..\lib" "-I." You just need to suppress the warning, and this will do it: This may offend your sensibilities, but it's very short and has no race conditions (as you'd have if you used &i). I personally upvoted this answer because by it's first line of text it helped me to understand the reason of this strange error message and what am I, poor idiot, doing :D. Not valid on Windows 64 - long is still 32-bit but pointers are 64-bit. - the incident has nothing to do with me; can I use this this way? How to use Slater Type Orbitals as a basis functions in matrix method correctly? The problem is not with casting, but with the target type loosing half of the pointer.
@Xax: Here's a fixed version, without the race condition: gist.github.com/depp/241d6f839b799042c409, gist.github.com/depp/3f04508a88a114734195, How Intuit democratizes AI development across teams through reusability. Keep in mind that thrArg should exist till the myFcn() uses it. From the question I presume the OP does. Can I tell police to wait and call a lawyer when served with a search warrant? You may declare a const int variable and cast its reference to the void*. You could use this code, and it would do the same thing as casting ptr to (char*). But then you need to cast your arguments inside your thread function which is quite unsafe cf. Thanks for contributing an answer to Stack Overflow! I usually have all automatic conversion warnings effective when developing in C, and I use explicit casting in order to suppress a specific . It is purely a compile-time directive which instructs the compiler to treat expression as if it had . Converts between types using a combination of implicit and user-defined conversions. Does melting sea ices rises global sea level? This forum has migrated to Microsoft Q&A. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. How do I check if a string represents a number (float or int)? The most general answer is - in no way.
B Programming Language | What is the History and Concept? Don't do that. C/C++ , Cerror: cast to 'void *' from smaller integer type 'int'. If the destination type is bool, this is a boolean conversion (see below). If any, how can the original function works without errors if we just ignore the warning.
error: cast from 'void*' to 'int' loses precision - Stack Overflow Since the 'size' argument for your function is the number of bytes each element in the array needs, I think casting the pointerto (char*) is appropriate. From what I read about casting in the C11 standard, my feeling is, that it is arguable to emit a warning on an explicit conversion.
Types - D Programming Language Thanks for contributing an answer to Stack Overflow!
Casting and type conversions - C# Programming Guide "I think what you should do is actually pass the address of the variable to the function" Not necessarily. Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. What happens if you typecast as unsigned first? Where does this (supposedly) Gibson quote come from? We have to pass address of the variable to the function because in function definition argument is pointer variable. If you preorder a special airline meal (e.g. Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? @jackdoe: It's a waste of human life to write code that "you may need in the future".
c - type casting integer to void* - Stack Overflow unsigned long call_fn = (unsigned long)FUNC; Asking for help, clarification, or responding to other answers. Find centralized, trusted content and collaborate around the technologies you use most. If the function had the correct signature you would not need to cast it explicitly. In a 64bit build a pointer is 64bit (contrary to a 32bit build, where it is 32bit), while an int is 32bit, so this assignment stores a 64bit value in a 32bit storage, which may result in a loss of information. x is a local variable and its lifetime ends as soon as control leaves the scope it was defined in.
[Solved] Properly casting a `void*` to an integer in C++ In both cases, converting the pointer to an integer type that's too small to represent all pointer values is a bug. The OP wanted to convert a pointer value to a int value, instead, most the answers, one way or the other, tried to wrongly convert the content of arg points to to a int value.
Type conversions - cplusplus.com ), Styling contours by colour and by line thickness in QGIS. Before I update Xcode, my project still can build and run normally with all devices. Thanks for contributing an answer to Stack Overflow! Wrong. Why is this sentence from The Great Gatsby grammatical? Thanks for contributing an answer to Stack Overflow! LLNL's tutorial is bad and they should feel bad. I have a two functions, one that returns an int, and one that takes a const void* as an argument.
Casting Pointers - IBM Identify those arcade games from a 1983 Brazilian music video, Relation between transaction data and transaction id, The difference between the phonemes /p/ and /b/ in Japanese. See also this documentation.. From and Into are generally intended to be lossless, infalliable conversions.as on the other hand can discard data and lead to bugs in some situations, for example casting a u64 to a usize may truncate the value on a 32-bit host. a cast of which the programmer should be aware of what (s)he is doing. You use the address-of operator & to do that. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Using Kolmogorov complexity to measure difficulty of problems? How to use Slater Type Orbitals as a basis functions in matrix method correctly? C++ how to get the address stored in a void pointer? SCAN_PUT(ATTR, NULL); for (i=0, j=0; j
Implicit Type Conversion in C with Examples - GeeksforGeeks This is not a conversion at all. [Solved] Error "Cast from pointer to smaller type 'int' | 9to5Answer rev2023.3.3.43278. A cast specifies a conversion from one type to another. This answer is incorrect for the reasons that have already been mentioned in the comment of, Error "Cast from pointer to smaller type 'int' loses information" in EAGLView.mm when update Xcode to 5.1 (5B130a), http://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models, http://stackoverflow.com/questions/18913906/xcode-5-and-ios-7-architecture-and-valid-architectures, How Intuit democratizes AI development across teams through reusability. The problem was there before, you just are being notified of it. Remarks. The 32 remaining bits stored inside int are insufficient to reconstruct a pointer to the thread function. to the original pointer: The following type designates an unsigned integer type with the It's an int type guaranteed to be big enough to contain a pointer. How can this new ban on drag possibly be considered constitutional? ^~~~~~~~~~~~~~~~~~~~~ It is easier to understand and write than any other assembly language. tialized" "-Wno-format" "-Wno-incompatible-pointer-types" "-Werror" "-dM" "-U_MSC_VER" "-D_TIMESPEC_DEFINED" "-D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_SECURE_NO_WA 7.1 New Cast Operations The C++ standard defines new cast operations that provide finer control than previous cast operations. Find centralized, trusted content and collaborate around the technologies you use most. "-I.." "-Iinclude\openflow" "-I..\include\openflow" "-Iinclude\openvswitch" "-I..\include\openvsw I agree passing a dynamically allocated pointer is fine (and I think the best way). : iPhone Retina 4-inch 64-bit) is selected. This explicit cast clearly tells the compiler "Shut up, I know that this code does not look correct, but I do know what I am doing". Error while setting app icon and launch image in xcode 5.1. Casting type int to const void* - C / C++ Linear regulator thermal information missing in datasheet. If pointers are 64 bits and ints are 32 bits, an int is too small to hold a pointer value. The calculated expression consists of two operations. . To learn more, see our tips on writing great answers. My code is all over the place now but I appreciate you all helping me on my journey to mastery! Implicit conversions - cppreference.com ../lib/odp-util.c:5601:9: note: expanded from macro 'SCAN_PUT' So the compiler is very picky here and the correct solution to make the code compile again and still let it show the exact same behavior like in Xcode 5.0 is to first cast to an integer type with a size that matches the one of a pointer and to then do a second cast to the int that we actually want: ids [i] = (int) (size_t)touch; Bulk update symbol size units from mm to map units in rule-based symbology. int, bigint, smallint, and tinyint (Transact-SQL) - SQL Server Are there tables of wastage rates for different fruit and veg? Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? You cannot just cast the 32-bit variable to a pointer, because that pointer on a 64-bit machine is twice as long. Connect and share knowledge within a single location that is structured and easy to search. Thanks Jonathan, I was thinking about my answer in another thread: AraK is correct, passing integers a pointers are not necessarily interchangeable. The difference between the phonemes /p/ and /b/ in Japanese, Styling contours by colour and by line thickness in QGIS, AC Op-amp integrator with DC Gain Control in LTspice, Identify those arcade games from a 1983 Brazilian music video. In 64-bit programs, the size of the pointer is 64 bits, and cannot be put into the int type, which remains 32-bit in almost all systems. That could create all kinds of trouble. The cast back to int * is not, though. You can convert the values from one type to another explicitly using the cast operator as follows (type_name) expression Projects. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. It's always a good practice to put your #define's in brackets to avoid such surprise. C99 standard library provides intptr_t and uintptr_t typedefs, which are supposed to be used whenever the need to perform such a cast comes about. In C (int)b is called an explicit conversion, i.e. Thanks for pointing that out. static const void* M_OFFSET = (void*)64*1024; Since gcc compiles that you are performing arithmetic between void* and an int ( 1024 ). Taking the above declarations of A, D, ch of the . Why does setupterm terminate the program? Please tell me error: cast from 'void*' to 'int' loses precision, How Intuit democratizes AI development across teams through reusability. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Asking for help, clarification, or responding to other answers. So you know you can cast it back like this. As for the stack, I've written a few libraries using pthreds, thus I don't agree that what you describe "is quite often the case". SCAN_SINGLE("skb_priority(", uint32_t, u32, OVS_KEY_ATTR_PRIORITY); Acidity of alcohols and basicity of amines. The dynamic_cast<>operator provides a way to check the actual type of a pointer to a polymorphic class. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. I need to cast the int from the first function so that I can use it as an argument for the second function. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? [that could be a TODO - not to delay solving the ICE]. If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. You can fix this error by replacing this line of code. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. privacy statement. A cast converts an object or value from one type to another. . SCAN_PUT_ATTR(key, ATTR, skey, FUNC); *sound/soc/codecs/tlv320aic32x4.c:1202:18: warning: cast to smaller integer type 'enum aic32x4_type' from 'void *' @ 2022-04-22 9:48 kernel test robot 0 siblings, 0 . The main point is: a pointer has a platform dependent size. Why is there a voltage on my HDMI and coaxial cables? ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~. There is absolutely not gurantee that sizeof(int) <= sizeof(void*). Clang warnings for an invalid casting? - The FreeBSD Forums Such a downcast makes no runtime checks to ensure that the object's runtime type is actually D, and may only be used safely if this precondition is guaranteed by other means, such as when implementing static polymorphism. So make sure you understand what you are doing! If we want to get the exact value of 7/5 then we need explicit casting from int to float: Example: int x=7, y=5; So the compiler is very picky here and the correct solution to make the code compile again and still let it show the exact same behavior like in Xcode 5.0 is to first cast to an integer type with a size that matches the one of a pointer and to then do a second cast to the int that we actually want: ids [i] = (int) (size_t)touch; // OK: lvalue denoting the original d object, // UB: the b subobject is not a base class subobject, // 6. array-to-pointer followed by upcast, https://en.cppreference.com/mwiki/index.php?title=cpp/language/static_cast&oldid=147983, when converting a 'pointer to object' to 'pointer to, the conversion from floating-point values, the conversion from bit-fields to rvalue references, the conversion from integral or enumeration values to enumeration, the conversion from integral or enumeration values to, the conversion from a member of base class type to, a standard-layout class object with no data members, a non-standard-layout union object and a non-static data, for base-to-derived pointer conversions and, the conversion to enumeration types with fixed underlying type, a standard-layout class might have a non-pointer-interconvertible, If the underlying type is not fixed, the behavior is undefined if the value of, If the underlying type is fixed, the result is the same as, one is a union object and the other is a non-static data member of that object, or. reinterpret_cast<void *>(42)). Have a question about this project? In Java, there are two types of casting: Widening Casting (automatically) - converting a smaller type to a larger type size. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. Asking for help, clarification, or responding to other answers. If this is the data to a thread procedure, then you quite commonly want to pass by value. Infact I know several systems where that does not hold. Making statements based on opinion; back them up with references or personal experience. If it's anything like cocos2d-iphone v2.x and just based on this slice of code in a core class I wager it's safe to say that cocos2d-x 2.x also is not compatible with 64 bit code, and you can expect all kinds of issues (not just compile-time but also runtime). If the original pointer value represents an address of a byte in memory that does not satisfy the alignment requirement of the target type, then the resulting pointer value is unspecified. Whats the grammar of "For those whose stories they are"? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Dinesh: could you please 1) show us those. Not the answer you're looking for? I would create a structure and pass that as void* to pthread_create. Cerror: cast to 'void *' from smaller integer type 'int' Find centralized, trusted content and collaborate around the technologies you use most. To access the object value, use the * dereference operator: int * p; assert (p == null ); p = new int (5); assert (p != null ); assert (*p == 5); (*p)++; assert (*p == 6); If a pointer contains a null value, it is not pointing to a valid object. Compile error on Android ARM Issue #163 cisco/ChezScheme
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