Compile error on Android ARM Issue #163 cisco/ChezScheme [] ExplanatioUnlike static_cast, but like const_cast, the reinterpret_cast expression does not compile to any CPU instructions (except when converting between integers and pointers or on obscure architectures where pointer representation depends on its type). Get the address of a callback function to call dynamically in C++, error: call of overloaded function ambiguous, error: cast from to unsigned int loses precision [-fpermissive]. I have a function with prototype void* myFcn(void* arg) which is used as the starting point for a pthread. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Yeah, the tutorial is doing it wrong. Please help me compile Chez Scheme. void* -> integer -> void* rather than integer -> void* -> integer. /** Dynamically allocate a 2d (x*y) array of elements of size _size_ bytes. reinterpret_cast conversion - cppreference.com Any help with this is appreciated. Making statements based on opinion; back them up with references or personal experience. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. @DavidHeffernan I rephrased that sentence a little. If pointers are 64 bits and ints are 32 bits, an int is too small to hold a pointer value. Implementation-dependent. Narrowing Casting (manually) - converting a larger type to a . 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; (void *)i Error: cast to 'void *' from smaller integer type 'int' PS: UBUNTUCLANG3.5 clang -O0 -std=gnu11 -march=native -lm -lpthread pagerank.c -o pagerank c pthreads 4 10.3k 2 21 2015-06-05 Please tell me error: cast from 'void*' to 'int' loses precision, How Intuit democratizes AI development across teams through reusability. This is why you got Error 1 C2036, from your post. windows meson: cast to smaller integer type 'unsigned long' from 'void *'. But you seem to suggest by your answer that the user can pass 5 to pthread_create and then perform the above cast to get it back. that any valid pointer to void can be converted to this type, then LLNL's tutorial is bad and they should feel bad. I guess the other important fact is that the cast operator has higher precedence that the multiplication operator. The problem is not with casting, but with the target type loosing half of the pointer. But this code pass the normal variable .. INT36-C. Converting a pointer to integer or integer to pointer If you need to keep the returned address, just keep it as void*. Netdev Archive on lore.kernel.org help / color / mirror / Atom feed * [mst-vhost:vhost 5/52] drivers/block/virtio_blk.c:539:21: warning: assignment to 'void *' from . 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. On most platforms pointers and longs are the same size, but ints and pointers often are not the same size on 64bit platforms. sound/soc/codecs/tlv320aic32x4.c:1202:18: warning: cast to smaller Or, they are all wrong. Returns a value of type new-type. The main point is: a pointer has a platform dependent size. Next, when doing pointer arithmetic, the addition operation will use the pointer's type to determine how many bytes to add to it when incrementing it. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. All character types are to be converted to an integer. Casting and type conversions - C# Programming Guide A cast specifies a conversion from one type to another. Type Casting in C Language with Examples - Dot Net Tutorials LLNL's tutorial is bad and they should feel bad. Don't do that. Does Counterspell prevent from any further spells being cast on a given turn? On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); A void pointer can be really useful if the programmer is not sure about the data type of data inputted by the end user. He should pass the address of the integer, the thread should get that address, Note: This is only appropriate is you cast the. But then you need to cast your arguments inside your thread function which is quite unsafe cf. Don't do that. iphone - Error "Cast from pointer to smaller type 'int' loses Identify those arcade games from a 1983 Brazilian music video. Does melting sea ices rises global sea level? To avoid truncating your pointer, cast it to a type of identical size. Cast characters to unsigned char before converting to larger integer sizes Created by Robert Seacord, last modified by Jill Britton on Oct 03, 2022 Signed character data must be converted to unsigned char before being assigned or converted to a larger signed type. What is the point of Thrower's Bandolier? 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. ncdu: What's going on with this second size column? Acidity of alcohols and basicity of amines. If you convert (void*) to (long) no precision is lost, then by assigning the (long) to an (int), it properly truncates the number to fit. No idea how it amassed 27 upvotes?! Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Find centralized, trusted content and collaborate around the technologies you use most. How to convert a factor to integer\numeric without loss of information? [that could be a TODO - not to delay solving the ICE]. It is commonly called a pointer to T and its type is T*. The 32 remaining bits stored inside int are insufficient to reconstruct a pointer to the thread function. 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. ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] SCAN_PUT_ATTR(mask, ATTR, smask, FUNC); Terrible solution. I'm new to coding and am trying to implement a simple program on my own, that prompts the user the number of residents in an apt complex, the prompts the user to enter the names and apt numbers of each resident. 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". Again, all of the answers above missed the point badly. Already on GitHub? This is flat out wrong. A nit: in your version, the cast to void * is unnecessary. you can pass the int value as void pointer like (void *)&n where n is integer, and in the function accept void pointer as parameter like void foo(void *n);and finally inside the function convert void pointer to int like, int num = *(int *)n;. How do I set, clear, and toggle a single bit? static_cast conversion - cppreference.com I don't see how anything bad can happen . The mapping in pointer<->integer casts is implementation defined, but the intent was that if the pointer type is large enough and isn't forcefully aligned (, But that's different. However the actual code in question contains an explicit c-style cast to int. error: cast from 'void*' to 'int' loses precision - Stack Overflow This method will not work on 64 bit Big Endian platform, so it unnecessarily breaks portability. ^~~~~~~~~~~~~~~~~~~~~ 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". rev2023.3.3.43278. Even though what you say regarding the lifetime of the object is true, integral types are too limited for a generic API. Whats the grammar of "For those whose stories they are"? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Xcode 5 and iOS 7: Architecture and Valid architectures, xcode build error: Semantic issue cast from pointer to smaller type 'int' loses information, Issues in handling touches on subviews(uiviews) in UIScrollView, Architecture linking error after Xcode 5.1 upgrade, iOS 7.1 gives error after updating to Xcode 5.1, Linker error in Xcode 5.1 with cocos2d-x 3 beta 2. c - type casting integer to void* - Stack Overflow ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The difference between the phonemes /p/ and /b/ in Japanese. Use of Void pointers in C programming language Where does this (supposedly) Gibson quote come from? Example: int x=7, y=5; float z; z=x/y; /*Here the value of z is 1*/. Cast Operations - Oracle I get the error: "cast to smaller integer type 'int' from 'string' (aka 'char *')" referencing line of code: while (isalpha(residents[i].name) == 0), How Intuit democratizes AI development across teams through reusability. 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. Api says this is how i should create thread: So if I want to pass an int what I think I should do is: The second example assumes that a pointer is wide enough to store an int. int, bigint, smallint, and tinyint (Transact-SQL) - SQL Server Do new devs get fired if they can't solve a certain bug? Offline ImPer Westermark over 11 years ago in reply to Andy Neil Except that you sometimes stores an integer in the pointer itself. . What I am saying is that it would be safer to use new(5) rather than 5 and deal with it appropriately at the other end. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin?). Thanks for contributing an answer to Stack Overflow! You can also convert values from one type to another explicitly using the cast operator (see Chapter 5 ): ( type_name) expression In the following example, the cast operator causes the division of one integer variable by another to be performed as a floating-point operation: int sum = 22, count = 5; double mean = (double)sum / count; This returns the first 32 bits of the pointer which may be the top or the bottom depending on big versus little endian, as comment #2 said. The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 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. Connect and share knowledge within a single location that is structured and easy to search. The bigint data type is intended for use when integer values might exceed the range that is supported by the int data type.. bigint fits between smallmoney and int in the data type precedence chart.. What is the purpose of non-series Shimano components? What is "cast from integer to pointer of different size" warning? Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. The point is (probably) that the value passed to the thread is an integer value, not really a 'void *'. clang warnings in v1.42 Issue #265 ocornut/imgui GitHub Implicit Type Conversion in C with Examples - GeeksforGeeks The only alternative is really to take time and fix all 64-bit code issues, of which there may be some non-trivial issues. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~. arrays - I get the error: "cast to smaller integer type 'int' from Why does setupterm terminate the program? Just re-enforcing the old behavior of Xcode 5.0 and earlier versions, that already cut away parts of the address by casting it to int, won't introduce any new bugs and avoids the need to learn and understand lots of implementation-internal cocos code. Using Kolmogorov complexity to measure difficulty of problems? If not, check the pointer size on your platform, define these typedefs accordingly yourself and use them. Why is there a voltage on my HDMI and coaxial cables? Bulk update symbol size units from mm to map units in rule-based symbology. Update: Today, i download the latest version of cocos2d-x (cocos2d-x 2.2.3). Find centralized, trusted content and collaborate around the technologies you use most. I am compiling this program in linux gcc compiler.. 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.
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