cast to void *' from smaller integer type 'int

Number Type Cast | Qt Forum The point is (probably) that the value passed to the thread is an integer value, not really a 'void *'. 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 This page was last modified on 12 February 2023, at 18:25. lexborisov Modest Public. [PATCH] platform/x86: hp-wmi: Fix cast to smaller integer type warning To learn more, see our tips on writing great answers. I have looked around and can't seem to find any information on how to do this. What is "cast from integer to pointer of different size" warning? 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). ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Use #include to define it. The proper way is to cast it to another pointer type. The most general answer is - in no way. cast to 'void *' from smaller integer type 'int' 471,961 Members | 900 Online. Are there tables of wastage rates for different fruit and veg? static const void* M_OFFSET = (void*)64*1024; Since gcc compiles that you are performing arithmetic between void* and an int ( 1024 ). Well occasionally send you account related emails. The result is the same as implicit conversion from the enum's underlying type to the destination type. what does it mean to convert int to void* or vice versa? void* to an array - C++ Forum - cplusplus.com Type Casting Of Pointers in C - Computer Notes Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. reinterpret_cast is a type of casting operator used in C++. Narrowing Casting (manually) - converting a larger type to a . Is it possible to create a concave light? If you preorder a special airline meal (e.g. If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. Implicit Type Conversion in C with Examples - GeeksforGeeks If the sizes are different then endianess comes into play. Why does setupterm terminate the program? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Setting a buffer of char* with intermediate casting to int*. If you are planning to use pthreads and you are planning to pass the pass function to pthread_create, you have to malloc/free the arguments you are planning to use (even if the threaded function just need a single int). Connect and share knowledge within a single location that is structured and easy to search. In the case of Widening Type Casting, the lower data type (having smaller size) is converted into the higher data type (having larger size). error: cast from 'void*' to 'int' loses precision - Stack Overflow For integer casts in specific, using into() signals that . 7.1 New Cast Operations The C++ standard defines new cast operations that provide finer control than previous cast operations. What I am trying to emphasis that conversion from int to pointer and back again can be frough with problems as you move from platform to platform. Does Counterspell prevent from any further spells being cast on a given turn? windows meson: cast to smaller integer type 'unsigned long' from 'void For the second example you can make sure that sizeof (int) <= sizeof (void *) by using a static_assert -- this way at least you'll get a notice about it. 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. Error while setting app icon and launch image in xcode 5.1. Does Counterspell prevent from any further spells being cast on a given turn? 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. If you need to keep the returned address, just keep it as void*. Properly casting a `void*` to an integer in C++ 24,193 Solution 1 I think using intptr_t is the correct intermediate here, since it's guaranteed to be large enough to contain the integral value of the void*, and once I have an integer value I can then truncate it without causing the compiler to complain. @Martin York: No, it doesn't depend on endiannness. should we also have a diagnostic for the (presumed) user error? 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. rev2023.3.3.43278. There's probably little you can do except look or hope for a fixed 2.x version or upgrade to 3.x (I would assume it's 64-bit safe but this is just a guess, do research this issue before you upgrade). Functions return bigint only if the parameter expression is a bigint data type. Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. If the source type is bool, the value false is converted to zero and the value true is converted to the value one of the destination type (note that if the destination type is int, this is an integer promotion, not an integer conversion). (void *)i Error: cast to 'void *' from smaller integer type 'int'. What is the difference between const int*, const int * const, and int const *? clang11 report error: cast to smaller integer type #82 - GitHub @DavidHeffernan, sane thread APIs wouldn't send integral data to the thread procedures, they would send pointers. with ids being an array of ints and touch being a pointer. If your code has the chance to ever be ported to some platform where this doesn't hold, this won't work. A cast converts an object or value from one type to another. Here is some piece of code where that error occur: /cocos2d-x-2.2.2/cocos2dx/platform/ios/EAGLView.mm:408:18: Cast from pointer to smaller type 'int' loses information. : iPhone Retina 4-inch 64-bit) is selected. The main point is: a pointer has a platform dependent size. I am compiling this program in linux gcc compiler.. How can this new ban on drag possibly be considered constitutional? Not the answer you're looking for? Click to see the query in the CodeQL repository. How to correctly cast a pointer to int in a 64-bit application? So you know you can cast it back like this. Thank you all for your feedback. Not the answer you're looking for? Thanks for contributing an answer to Stack Overflow! A void pointer can be really useful if the programmer is not sure about the data type of data inputted by the end user. Windows has 32 bit long only on 64 bit as well. Thanks for contributing an answer to Stack Overflow! Mutually exclusive execution using std::atomic? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 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. @LearnCocos2D: so, how can i "overcome" the error without editing any not-my-code or in-library-file lines? This will get you a pointer from a 32 bit offset: A function pointer is incompatible to void* (and any other non function pointer). From that point on, you are dealing with 32 bits. You use the address-of operator & to do that int x = 10; void *pointer = &x; And in the function you get the value of the pointer by using the dereference operator *: int y = * ( (int *) pointer); Share Improve this answer Follow edited Apr 15, 2013 at 13:58 answered Apr 15, 2013 at 13:53 Some programmer dude 394k 35 393 602 1 But the problem has still happened. whether it was an actual problem is a different matter though. [Solved] Error "Cast from pointer to smaller type 'int' | 9to5Answer LLNL's tutorial is bad and they should feel bad. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Where does this (supposedly) Gibson quote come from? Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? 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. Even if you are compiling your program for a 32-bit computer, you should fix your code to remove these warnings, to ensure your code is easily portable to 64-bit. To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 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. How Intuit democratizes AI development across teams through reusability. The preprocesor absolutely will not perform arithmetic. How to tell which packages are held back due to phased updates, Identify those arcade games from a 1983 Brazilian music video. ../lib/odp-util.c:5603:13: note: expanded from macro 'SCAN_PUT' Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? It is commonly called a pointer to T and its type is T*. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. Star 675. How to make compiler not show int to void pointer cast warnings, incompatible pointer types assigning to 'void (*)(void *)' from 'int (int *)'. Find centralized, trusted content and collaborate around the technologies you use most. ", "!"? For example, if youwrite ((int*)ptr + 1), it will add 4 bytes to the pointer, because "ints" are 4 bytes each. "After the incident", I started to be more careful not to trip over things. Otherwise, if the original pointer value points to an object a, and there is an object b of the . This is memory reinterpretation - a completely unacceptable way to do what the OP is trying to do. cast to void *' from smaller integer type 'int this way you won't get any warning. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. If the function had the correct signature you would not need to cast it explicitly. */void **MatrixIB (unsigned long x, unsigned long y, int size){ void *ptr; void **returnPtr; register unsigned long i, j; sound/soc/codecs/tlv320aic32x4.c:1202:18: warning: cast to smaller Note the difference between the type casting of a variable and type casting of a pointer. privacy statement. I assumed that gcc makes a 65536 out of my define, but I was wrong. If you call your thread creation function like this, then the void* arriving inside of myFcn has the value of the int you put into it. Acidity of alcohols and basicity of amines. This forum has migrated to Microsoft Q&A. In my case, I was using a 32-bit value that needed to be passed to an OpenGL function as a void * representing an offset into a buffer. Issues. Yeah, the tutorial is doing it wrong. The following behavior-changing defect reports were applied retroactively to previously published C++ standards. Notifications. Casting and type conversions - C# Programming Guide vegan) just to try it, does this inconvenience the caterers and staff? Evaluate integer expressions in a larger size before comparing or assigning to that size.Note that (time_+t)-1 also complies with INT31-C-EX3. Where does this (supposedly) Gibson quote come from? Already on GitHub? Such pointers can be stored in 32-bit data types (for instance, int, DWORD). Since gcc compiles that you are performing arithmetic between void* and an int (1024). Why is there a voltage on my HDMI and coaxial cables? @DietrichEpp can you explain what is race condition with using. Replacing broken pins/legs on a DIP IC package, AC Op-amp integrator with DC Gain Control in LTspice. Please note that the error I am receiving is "cast to smaller integer type 'int' from 'string' (aka 'char *')" referencing line of code: while (isalpha(residents[i].name) == 0). He should pass the address of the integer, the thread should get that address, Note: This is only appropriate is you cast the. Did i have to face to unexpected runtime issues, i guess not, i've found another discussion on this -. What is the purpose of non-series Shimano components? How can this new ban on drag possibly be considered constitutional? (i.e. The reinterpret_cast makes the int the size of a pointer and the warning will stop. warning C4311: 'type cast': pointer truncation from 'void *' to 'long' in ECPG test files. Here is my code: I already tried (void*)M_TABLE_SIZE but then I get an error that I cannot use the * operator. Thus as a result it may be less error prone to generate a pointer dynamcially and use that. On many systems, an 8-bit unsigned int can be stored at any address while an unsigned 32-bit int must be aligned on an address that is a multiple of 4. This is known as implicit type casting or type promotion, compiler automatically converts smaller data type to larger data type. Casting type int to const void* - C / C++ Getting Command /bin/sh failed with exit code 65 Error with Xcode 5.1 . So make sure you understand what you are doing! So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. You can convert the values from one type to another explicitly using the cast operator as follows (type_name) expression How to convert a factor to integer\numeric without loss of information? converted back to pointer to void, and the result will compare equal Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. If the original type is a void *, converting to an int may lose date on platforms where sizeof(void *) != sizeof(int) (which is true of LP64 programming model). 10) A prvalue of type pointer to void (possibly cv-qualified) can be converted to pointer to any object type. How do I set, clear, and toggle a single bit? @jackdoe: It's a waste of human life to write code that "you may need in the future". Thanks for pointing that out. Connect and share knowledge within a single location that is structured and easy to search. 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. This is flat out wrong. Why is this sentence from The Great Gatsby grammatical? How to notate a grace note at the start of a bar with lilypond? How to use Slater Type Orbitals as a basis functions in matrix method correctly? windows meson: cast to 'HANDLE' (aka 'void *') from smaller integer The program can be set in such a way to ask the user to inform the type of data and . Clang warnings for an invalid casting? - The FreeBSD Forums ^~~~~~~~~~~~~~~~~~~~~ error: cast from pointer to smaller type 'unsigned int' loses Note:You might receive a runtime exception if the pointer contains a value unsuitable for the context. This is what the second warning is telling you. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Use of Void pointers in C programming language 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. Cast a smaller integer to a larger integer - community - The Rust What is the point of Thrower's Bandolier? What video game is Charlie playing in Poker Face S01E07? equal to the original pointer: First you are using a define, which is not a variable. 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. 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;. @Shahbaz you could but I will not suggest to a C newbie to use globals. If any, how can the original function works without errors if we just ignore the warning. Maybe you can try this too. Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. Converting one datatype into another is known as type casting or, type-conversion. rev2023.3.3.43278. int, bigint, smallint, and tinyint (Transact-SQL) - SQL Server To learn more, see our tips on writing great answers. "-D_FILE_OFFSET_BITS=64" "-Wall" "-Winvalid-pch" "-g" "-Wthread-safety" "-Wno-microsoft-enum-forward-reference" "-Wno-unused-function" "-Wno-sometimes-unini This will only compile if the destination type is long enough. And in this context, it is very very very common to see programmers lazily type cast the. "-I.." "-Iinclude\openflow" "-I..\include\openflow" "-Iinclude\openvswitch" "-I..\include\openvsw Basically its a better version of (void *)i. Changing the type of ids would be the cleanest solution, but I decided against it when being confronted with this issue myself, as it only introduced a lot of issues with other code that is relying on ids being an int-array. Cast unsigned char (uint8 *) pointer to unsigned long (uint32 *) pointer What you do here is undefined behavior, and undefined behavior of very practical sort. It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. FAILED: lib/libopenvswitch.a.p/odp-util.c.obj Java Type Casting (With Examples) - Programiz Don't do that. Remembering to delete the pointer after use so that we don't leak. property that any valid pointer to void can be converted to this type, ), For those who are interested. *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 . 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. I cannot reverse my upvote of user384706's answer, but it's wrong. */ >> -bool >> +enum conversion_safety >> unsafe_conversion_p (tree type, tree expr, bool . ^~~~~~~~~~~~~~~~~~~ Visit Microsoft Q&A to post new questions. You think by casting it here that you are avoiding the problem! To learn more, see our tips on writing great answers. 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]. use $(ARCHS_STANDARD_32_BIT) at Architecture instead of $(ARCHS_STANDARD). "clang" "-Ilib\libopenvswitch.a.p" "-Ilib" "-I..\lib" "-I." Then I build my project, I get the error "Cast from pointer to smaller type 'int' loses information" in EAGLView.mm file (line 408) when 64-bit simulators (e.g. Hence there is no loss in data. returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); A sane compiler may throw a warning on lines like this but by no way it should throw an error, because this code is NOT wrong, it is just potentially error-prone, but can be perfectly valid. Put your define inside a bracket: without a problem. static_cast on the other hand should deny your stripping away the const qualifier. There's no proper way to cast this to int in general case. cast operators [edit] When an expression is used in the context where a value of a different type is expected, conversionmay occur: intn =1L;// expression 1L has type long, int is expectedn =2.1;// expression 2.1 has type double, int is expectedchar*p =malloc(10);// expression malloc(10) has type void*, char* is expected Casting a pointer to void* and back is valid use of reinterpret_cast<>. Java Type Casting. Whats the grammar of "For those whose stories they are"? Why does Mister Mxyzptlk need to have a weakness in the comics? Casting an open pointer to other pointer types and casting other pointer types to an open pointer does not result in a compile time error. Only the following conversions can be done with static_cast, except when such conversions would cast away constness or volatility. The code ((void*)ptr + 1) does not work, because the compiler has no idea what size "void" is, and therefore doesn't know how many bytes to add. Fork 63. 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. 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. In Java, there are two types of casting: Widening Casting (automatically) - converting a smaller type to a larger type size. 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 . Can we typecast void into int? - Quora STR34-C. Cast characters to unsigned char before converting to larger Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Just edited. In simple example code like this it's very easy to convince yourself that there's no problem, but in more elaborate real-world scenarios it's very easy to make this mistake inadvertently. INT36-C. Converting a pointer to integer or integer to pointer

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