Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Dinesh: could you please 1) show us those. You need to cast the void* pointer to a char* pointer - and then dereference that char* pointer to give you the char that it points to! 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). 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. There's no proper way to cast this to int in general case. Casting a pointer to void* and back is valid use of reinterpret_cast<>. To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. 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. error: comparison between pointer and integer ('int' and 'string' (aka 'char *')), CS50 Caesar program is working but check50 says it isn't. Any expression can be cast to type void (which means that the result of the expression is ignored), but it's not legal to cast an expression of type void to type int not least because the result of such a cast wouldn't make any sense. The pointer doesn't actually point to anything, but it's the result of an earlier cast from an integer to a pointer (e.g. By clicking Sign up for GitHub, you agree to our terms of service and The program can be set in such a way to ask the user to inform the type of data and . But gcc always give me a warning, that i cannot cast an int to a void*. 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. B language was designed to develop . Connect and share knowledge within a single location that is structured and easy to search. How Intuit democratizes AI development across teams through reusability. It modifies >> Wconversion-real.c, Wconversion-real-integer.c and pr35635.c to be more >> specific > > If the patch passes existing tests, I'd be inclined to leave them > tests alone and add new ones that are specific to what this patch > changes. Infact I know several systems where that does not hold. "After the incident", I started to be more careful not to trip over things. (int*)Pc = pa; After the execution of the above code all the three pointers, i.e., Pa, Pd, and Pc, point to the value 150. Why did Ukraine abstain from the UNHRC vote on China? pthread passes the argument as a void*. As Ferruccio said, int must be replaced with intptr_t to make the program meaningful. Asking for help, clarification, or responding to other answers. The best way is, if one can, do not do such casting, instead, if the same memory address has to be shared for pointer and int (e.g. Using Kolmogorov complexity to measure difficulty of problems? ../lib/odp-util.c:5489:33: note: expanded from macro 'SCAN_PUT_ATTR' If this is the data to a thread procedure, then you quite commonly want to pass by value. LLNL's tutorial is bad and they should feel bad. @Shahbaz you could but I will not suggest to a C newbie to use globals. You are right! rev2023.3.3.43278. To learn more, see our tips on writing great answers. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Connect and share knowledge within a single location that is structured and easy to search. To learn more, see our tips on writing great answers. Don't do that. For example, if you want to store a 'long' value into a simple integer then you can type cast 'long' to 'int'. Functions return bigint only if the parameter expression is a bigint data type. In such condition type conversion (type promotion) takes place to avoid loss of data. Using indicator constraint with two variables. Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] Do new devs get fired if they can't solve a certain bug? SCAN_PUT_ATTR(mask, ATTR, smask, FUNC); The problem was there before, you just are being notified of it. Mutually exclusive execution using std::atomic? What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? ^~~~~~~~~~~~~~~~~~~ ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' Where does this (supposedly) Gibson quote come from? 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. But the problem has still happened. 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). @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. 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. what happens when we typecast normal variable to void* or any pointer variable? How Intuit democratizes AI development across teams through reusability. 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. How to tell which packages are held back due to phased updates, Identify those arcade games from a 1983 Brazilian music video. The calculated expression consists of two operations. If not, check the pointer size on your platform, define these typedefs accordingly yourself and use them. I'm trying to create a void* from an int. Thanks for contributing an answer to Stack Overflow! unsigned long call_fn = (unsigned long)FUNC; I am compiling this program in linux gcc compiler.. } SCAN_END_SINGLE(ATTR) I cannot reverse my upvote of user384706's answer, but it's wrong. 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;. Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. In C (int)b is called an explicit conversion, i.e. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? 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. A void pointer can be really useful if the programmer is not sure about the data type of data inputted by the end user. } SCAN_END_SINGLE(ATTR) This is an old C callback mechanism so you can't change that. Put your define inside a bracket: without a problem. 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. 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. Don't pass your int as a void*, pass a int* to your int, so you can cast the void* to an int* and copy the dereferenced pointer to your int. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Bulk update symbol size units from mm to map units in rule-based symbology. In this case, casting the pointer back to an integer is meaningless, because . 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. A missing cast in the new fast > enumeration code. This page was last modified on 12 February 2023, at 18:25. You are just making it bigger by tricking the compiler and the ABI. A long long would not work for 32bit systems and a long would not work for 64 bit Windows (while 64bit Unix and Unix-like systems like OS X use the LP64 data model, in which a long is 64bit, 64bit Windows uses the LLP64 data model, in which a long has a size of 32bit (http://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models)). No sense in writing a few dozen lines of extra code just to get a bunch of numbered threads. Visit Microsoft Q&A to post new questions. The value of float variable is= 37.75. Implementing From will result in the Into implementation but not vice-versa. All float types are to be converted to double. How do I force make/GCC to show me the commands? On most platforms pointers and longs are the same size, but ints and pointers often are not the same size on 64bit platforms. Making statements based on opinion; back them up with references or personal experience. Not the answer you're looking for? And you can't pass a pointer to a stack based object from the other thread as it may no longer be valid. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. If you need to keep the returned address, just keep it as void*. *PATCH] platform/x86: hp-wmi: Fix cast to smaller integer type warning @ 2023-01-23 13:28 Hans de Goede 2023-01-23 13:56 ` Hans de Goede 0 siblings, 1 reply; 2+ messages in thread From: Hans de Goede @ 2023-01-23 13:28 UTC (permalink / raw) To: Mark Gross Cc: Hans de Goede, Andy Shevchenko, platform-driver-x86, kernel test robot Fix the following . and how to print the thread id of 2d array argument? This forum has migrated to Microsoft Q&A. Making statements based on opinion; back them up with references or personal experience. @BlueMoon Thanks a lot! Safe downcast may be done with dynamic_cast. "clang" "-Ilib\libopenvswitch.a.p" "-Ilib" "-I..\lib" "-I." You can use any other pointer, or you can use (size_t), which is 64 bits. Thanks. converted back to pointer to void, and the result will compare equal 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: I am using size_t here, because it is always having the same size as a pointer, no matter the platform. Asking for help, clarification, or responding to other answers. The difference between the phonemes /p/ and /b/ in Japanese. The problem is not with casting, but with the target type loosing half of the pointer. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. SCAN_PUT_ATTR(key, ATTR, skey, FUNC); Thanks Jonathan, I was thinking about my answer in another thread: AraK is correct, passing integers a pointers are not necessarily interchangeable. I agree passing a dynamically allocated pointer is fine (and I think the best way). What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? vegan) just to try it, does this inconvenience the caterers and staff? If the function had the correct signature you would not need to cast it explicitly. rev2023.3.3.43278. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. what does it mean to convert int to void* or vice versa? You need to pass an actual pointer. Does ZnSO4 + H2 at high pressure reverses to Zn + H2SO4? whether it was an actual problem is a different matter though. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? this question. Note:You might receive a runtime exception if the pointer contains a value unsuitable for the context. The main point is: a pointer has a platform dependent size. Maybe you can try this too. Thanks for pointing that out. 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. ../lib/odp-util.c:5603:13: note: expanded from macro 'SCAN_PUT' What is the point of Thrower's Bandolier? We have to pass address of the variable to the function because in function definition argument is pointer variable. SCAN_PUT(ATTR, NULL); 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. Now, what happens when I run it with the thread sanitizer? Thanks for contributing an answer to Stack Overflow! How do I set, clear, and toggle a single bit? The compiler issues the "cast from integer to pointer of different size" warning whenever the value of an integer is converted to a pointer, especially when the memory allocated to a pointer is smaller than the memory allocated to an integer data type. I'm unfamiliar with XCode, but the solution should be something like follows: Most of the "solutions" above can lose part of the pointer address when casting to a smaller type. How do I count the number of sentences in C using ". It is commonly called a pointer to T and its type is T*. (int) pthread_self() 64int48intuintptr_t (unsigned int) By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. For integer casts in specific, using into() signals that . If the destination type is bool, this is a boolean conversion (see below). 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.. Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. to your account, [87/252] Compiling C object lib/libopenvswitch.a.p/odp-util.c.obj If any, how can the original function works without errors if we just ignore the warning. Does Counterspell prevent from any further spells being cast on a given turn? Star 675. You cannot just cast the 32-bit variable to a pointer, because that pointer on a 64-bit machine is twice as long. 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? The point is (probably) that the value passed to the thread is an integer value, not really a 'void *'. AC Op-amp integrator with DC Gain Control in LTspice. . Does a summoned creature play immediately after being summoned by a ready action? *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 .