cast to void *' from smaller integer type 'int cast to void *' from smaller integer type 'int

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. 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). 1. It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. This page has been accessed 1,655,678 times. actually no, as int my be a smaller type than a pointer ;-) But, of course with int64_t it works fine. Using Kolmogorov complexity to measure difficulty of problems? with ids being an array of ints and touch being a pointer. To learn more, see our tips on writing great answers. RNINGS" "-D_CRT_SECURE_NO_DEPRECATE" -MD -MQ lib/libopenvswitch.a.p/odp-util.c.obj -MF "lib\libopenvswitch.a.p\odp-util.c.obj.d" -o lib/libopenvswitch.a.p/od C/C++ , Cerror: cast to 'void *' from smaller integer type 'int'. Anw, the project still build and run normally when i use Xcode 5.0 with iOS 7.0. If you preorder a special airline meal (e.g. 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. Projects. Mutually exclusive execution using std::atomic? 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. You should perform type conversion based on 64bit build system because the type "int" supports only -32768 ~ 32768. 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. Thanks for contributing an answer to Stack Overflow! Not the answer you're looking for? Even though what you say regarding the lifetime of the object is true, integral types are too limited for a generic API. But the problem has still happened. equal to the original pointer: First you are using a define, which is not a variable. The following behavior-changing defect reports were applied retroactively to previously published C++ standards. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. How to convert a factor to integer\numeric without loss of information? return ((void **) returnPtr);} /* Matrix() */. Implicit conversions - cppreference.com GitHub Skip to content Product Solutions Open Source Pricing Sign in Sign up smadaminov / ovs-dpdk-meson-issues Public Notifications Fork 1 Star 1 Code Issues 66 Pull requests Actions Projects 1 Security Insights New issue ../lib/odp-util.c:5658:9: note: expanded from macro 'SCAN_END_SINGLE' Returns a value of type new-type. I agree passing a dynamically allocated pointer is fine (and I think the best way). Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Cast a smaller integer to a larger integer - community - The Rust what does it mean to convert int to void* or vice versa? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Then i can continue compiling. 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; It is done by the compiler on its own, without any external trigger from the user. Use returnPtr[j] = (void *) ((long)ptr + i); ). If you need to keep the returned address, just keep it as void*. Note:You might receive a runtime exception if the pointer contains a value unsuitable for the context. 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; My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? An object pointer (including void*) or function pointer can be converted to an integer type using reinterpret_cast. Infact I know several systems where that does not hold. Where does this (supposedly) Gibson quote come from? This is not a conversion at all. 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. This will get you a pointer from a 32 bit offset: A function pointer is incompatible to void* (and any other non function pointer). However even though their types are different, the address is going to be the same. The int data type is the primary integer data type in SQL Server. byte -> short -> char -> int -> long -> float -> double. reinterpret_cast conversion - cppreference.com Asking for help, clarification, or responding to other answers. Basically its a better version of (void *)i. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. It's always a good practice to put your #define's in brackets to avoid such surprise. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. In C (int)b is called an explicit conversion, i.e. 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. But assuming that it is, as long as the caller and the callee agree, you can do that sort of thing. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. [PATCH] platform/x86: hp-wmi: Fix cast to smaller integer type warning 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. The problem just occur with Xcode 5.1. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Noncompliant Code Example (memset())For historical reasons, certain C Standard functions accept an argument of type int and convert it to either unsigned char or plain char. Not the answer you're looking for? Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. (i.e. Converting one datatype into another is known as type casting or, type-conversion. Typecasting - Data Types - Language Basics - MQL4 Reference I would create a structure and pass that as void* to pthread_create. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, You should be doing int x = *((int *)arg); You are casting from void * to int that is why you get the warning. (void *)i Error: cast to 'void *' from smaller integer type 'int'. Making statements based on opinion; back them up with references or personal experience. To avoid truncating your pointer, cast it to a type of identical size. error: comparison between pointer and integer ('int' and 'string' (aka 'char *')), CS50 Caesar program is working but check50 says it isn't. If any, how can the original function works without errors if we just ignore the warning. *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 . Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul This is an old C callback mechanism so you can't change that. Connect and share knowledge within a single location that is structured and easy to search. x is a local variable and its lifetime ends as soon as control leaves the scope it was defined in. As Ferruccio said, int must be replaced with intptr_t to make the program meaningful. Since all pointers on 64-bit Windows are 64 bits, you are growing the data size from 32 bits backto 64 bits. Only the following conversions can be done with static_cast, except when such conversions would cast away constness or volatility. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? What happens if you typecast as unsigned first? even though the compiler doesn't know you only ever pass myFcn to pthread_create in conjunction with an integer. Any help with this is appreciated. 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;. Asking for help, clarification, or responding to other answers. Java Type Casting - W3Schools All character types are to be converted to an integer. 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. Implicit conversions - cppreference.com A cast specifies a conversion from one type to another. Cast unsigned char (uint8 *) pointer to unsigned long (uint32 *) pointer Whats the grammar of "For those whose stories they are"? 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. To learn more, see our tips on writing great answers. On all of them int is 32bit, not 16bit. 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". What is "cast from integer to pointer of different size" warning? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Can we typecast void into int? - Quora itch" "-I..\include\windows" "-Iinclude" "-I..\include" "-I..\datapath-windows\include" "-IC:\PTHREADS-BUILT\include" "-Xclang" "-fcolor-diagnostics" "-pipe" Use #include to define it. You are getting warnings due to casting a void* to a type of a different size. Just want to point out that the purpose of threads is, +1 absolutely true, but if you take you time to write struct {}, you can save a lot of troubles in the future when you want to receive/send more data then just an int. ../lib/odp-util.c:5658:9: note: expanded from macro 'SCAN_END_SINGLE' How to Cast a void* ponter to a char without a warning? ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' 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). 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. @Martin York: No, it doesn't depend on endiannness. 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. 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. : iPhone Retina 4-inch 64-bit) is selected. 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). If you really need such trickery, then consider one of dedicated types, which are intptr_t and uintptr_t. I usually have all automatic conversion warnings effective when developing in C, and I use explicit casting in order to suppress a specific . pthread create managing values generated in function (in c), Establishing TCP socket connection between PHP client and C server on Ubuntu. void* to an array - C++ Forum - cplusplus.com B programing language is a language based on basic combined programming or a BCPL, and it is the precursor of the C programming language. SCAN_PUT(ATTR, NULL); You are getting warnings due to casting a void* to a type of a different size. The value of float variable is= 37.75. However the actual code in question contains an explicit c-style cast to int. 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 But this code pass the normal variable .. 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. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. Notifications. I need to cast the int from the first function so that I can use it as an argument for the second function. I'm trying to learn pthreads and thing that keeps bugging me is how do i really pass argument to the function. 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. Java Type Casting (With Examples) - Programiz 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. The program can be set in such a way to ask the user to inform the type of data and . Visit Microsoft Q&A to post new questions. It's an int type guaranteed to be big enough to contain a pointer. what happens when we typecast normal variable to void* or any pointer variable? C99 defines the types "intptr_t" and "uintptr_t" which do . You can use a 64 bits integer instead howerver I usually use a function with the right prototype and I cast the function type : Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? Clang warnings for an invalid casting? - The FreeBSD Forums If you preorder a special airline meal (e.g. We have to pass address of the variable to the function because in function definition argument is pointer variable. But I'm nitpicking .. @BlueMoon Thanks a lot! Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? SCAN_PUT_ATTR(key, ATTR, skey, FUNC); for (i=0, j=0; jint, bigint, smallint, and tinyint (Transact-SQL) - SQL Server Press question mark to learn the rest of the keyboard shortcuts. Asking for help, clarification, or responding to other answers. static_cast conversion - cppreference.com This is not even remotely "the correct answer". -1, Uggh. Why do small African island nations perform better than African continental nations, considering democracy and human development? [Solved] Error "Cast from pointer to smaller type 'int' | 9to5Answer Remembering to delete the pointer after use so that we don't leak. You cannot just cast the 32-bit variable to a pointer, because that pointer on a 64-bit machine is twice as long. Create an account to follow your favorite communities and start taking part in conversations. 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). Apparently the clang version in Xcode 5.1 and above is more strict about potential 32bit vs. 64 bit incompatibilities in source code than older clang versions have been. eg. Narrowing Casting (manually) - converting a larger type to a . 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! long guarantees a pointer size on Linux on any machine. If that happens soon after the call to pthread_create() then you have a race condition, because there's a chance that the thread will attempt to read x's value after it's life has ended, which invokes undefined behavior. // 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. cast to 'double *' from smaller integer type 'unsigned int' The C compiler is gcc, clang version 3.9.1, target aarch64--linux-android, thread model posix. So you know you can cast it back like this. If the value in a pointer is cast to a different type and it does not have the correct alignment for the new type, the behavior is undefined. How to correctly cast a pointer to int in a 64-bit application? If the value is ever used as pointer again that will prove to be an extremely bad idea. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. ncdu: What's going on with this second size column? A missing cast in the new fast > enumeration code. } SCAN_END_SINGLE(ATTR) Usually that means the pointer is allocated with. To learn more, see our tips on writing great answers. this way I convert an int to a void* which is much better than converting a void* to an int. rev2023.3.3.43278. You can fix this error by replacing this line of code. However, you are also casting the result of this operation to (void*). B Programming Language | What is the History and Concept? The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. The reinterpret_cast makes the int the size of a pointer and the warning will stop. "because the type "int" supports only -32768 ~ 32768" This is not true for any modern desktop or mobile OS or any OS that is targeted by cocos2d-x. I need to convert the argument to an int for later use: The compiler (GCC version 4.2.4) returns the error: You can cast it to an intptr_t type. While working with Threads in C, I'm facing the warning, "warning: cast to pointer from integer of different size". Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, "what happen when typcating normal variable to void* or any pointer variable?"