cast to void *' from smaller integer type 'int

unsigned long call_fn = (unsigned long)FUNC; What happens if you typecast as unsigned first? Actions. The cast back to int * is not, though. Press question mark to learn the rest of the keyboard shortcuts. In the first example, the variable c1 of the char type is converted to a temporary variable of the int type, because the second operand in the division operation, the constant 2, is of the higher type int. 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. On most platforms pointers and longs are the same size, but ints and pointers often are not the same size on 64bit platforms. Please tell me error: cast from 'void*' to 'int' loses precision, How Intuit democratizes AI development across teams through reusability. Find centralized, trusted content and collaborate around the technologies you use most. Type casting is when you assign a value of one primitive data type to another type. How to use Slater Type Orbitals as a basis functions in matrix method correctly? 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. My code is all over the place now but I appreciate you all helping me on my journey to mastery! We have to pass address of the variable to the function because in function definition argument is pointer variable. 1. Disconnect between goals and daily tasksIs it me, or the industry? Converting a pointer to an integer whose result cannot represented in the integer type is undefined behavior is C and prohibited in C++. If the object expression refers or points to is actually a base class subobject of an object of type D, the result refers to the enclosing object of type D. Otherwise, the behavior is undefined: When the target type is bool (possibly cv-qualified), the result is false if the original value is zero and true for all other values. If your code has the chance to ever be ported to some platform where this doesn't hold, this won't work. Mutually exclusive execution using std::atomic? Why is this sentence from The Great Gatsby grammatical? That's probably going to be true for most platforms you will ever encounter, but it's not a guarantee; it's implementation-dependent. Converting one datatype into another is known as type casting or, type-conversion. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin?). ../lib/odp-util.c:5601:9: note: expanded from macro 'SCAN_PUT' To be honest, I think, clang is too restrictive here. Issues. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Connect and share knowledge within a single location that is structured and easy to search. Thanks for contributing an answer to Stack Overflow! This is known as implicit type casting or type promotion, compiler automatically converts smaller data type to larger data type. Does Counterspell prevent from any further spells being cast on a given turn? what happens when we typecast normal variable to void* or any pointer variable? Surely the solution is to change the type of ids from int to type that is sufficiently large to hold a pointer. I'm using cocos2d-x-2.2.2. Windows has 32 bit long only on 64 bit as well. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You are getting warnings due to casting a void* to a type of a different size. @jackdoe: It's a waste of human life to write code that "you may need in the future". 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. (Also, check out how it prints "5" twice), passing a unique pointer to each thread wont race, and you can get/save any kind of information in the th struct. If not, check the pointer size on your platform, define these typedefs accordingly yourself and use them. casting from int to void* and back to int. Making statements based on opinion; back them up with references or personal experience. Thanks for contributing an answer to Stack Overflow! Referring to N1570 7.20.1.4/p1 (Integer types capable of holding object pointers): The following type designates a signed integer type with the property for (i=0, j=0; j to define it. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. For example, if youwrite ((int*)ptr + 1), it will add 4 bytes to the pointer, because "ints" are 4 bytes each. If any, how can the original function works without errors if we just ignore the warning. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. How do I work around the GCC "error: cast from SourceLocation* to int loses precision" error when compiling cmockery.c? This forum has migrated to Microsoft Q&A. How to correctly cast a pointer to int in a 64-bit application? That's not a good idea if the original object (that was cast to void*) was an integer. should we also have a diagnostic for the (presumed) user error? This page was last modified on 12 February 2023, at 18:25. As was pointed out by Martin, this presumes that sizeof(void*)>=sizeof(int). What video game is Charlie playing in Poker Face S01E07? There's no proper way to cast this to int in general case. BUT converting a pointer to void* and back again is well supported (everywhere). 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. Do new devs get fired if they can't solve a certain bug? So you could do this: Note: As sbi points out this would require a change on the OP call to create the thread. In the best case this will give the same results as the original code, with no advantages, but in the worst case it will fail in multiple catastrophic ways (type punning, endianness, less efficient, etc. In such condition type conversion (type promotion) takes place to avoid loss of data. ), For those who are interested. */ >> -bool >> +enum conversion_safety >> unsafe_conversion_p (tree type, tree expr, bool . This is why you got Error 1 C2036, from your post. *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 . How to use Slater Type Orbitals as a basis functions in matrix method correctly? 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". The text was updated successfully, but these errors were encountered: You signed in with another tab or window. 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 It generally takes place when in an expression more than one data type is present. "I think what you should do is actually pass the address of the variable to the function" Not necessarily. The program can be set in such a way to ask the user to inform the type of data and . And when assigning to a void pointer, all type information is lost. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. There are ways to prevent this: pass a dynamic allocated argument if your not the passing thread is not static or if your argument is a local variable, otherwise there is no issue. that any valid pointer to void can be converted to this type, then ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' Can Martian regolith be easily melted with microwaves? Here is my code: I already tried (void*)M_TABLE_SIZE but then I get an error that I cannot use the * operator. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? 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). 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. Sign in Not the answer you're looking for? Click to see the query in the CodeQL repository. Otherwise, if the original pointer value points to an object a, and there is an object b of the . What is the point of Thrower's Bandolier? Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? (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 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~. Once you manage to make this cast, then what?! 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. } SCAN_END_SINGLE(ATTR) 471,961 Members | 900 Online. Thanks for contributing an answer to Stack Overflow! Recovering from a blunder I made while emailing a professor. And in the function you get the value of the pointer by using the dereference operator *: Please read why glib provide macros for this kind of conversions, there's no need to repeat the text here. This page has been accessed 1,655,678 times. A void pointer can be really useful if the programmer is not sure about the data type of data inputted by the end user. 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. - the incident has nothing to do with me; can I use this this way? How Intuit democratizes AI development across teams through reusability. How can this new ban on drag possibly be considered constitutional? then converted back to pointer to void, and the result will compare If you preorder a special airline meal (e.g. How to make compiler not show int to void pointer cast warnings, incompatible pointer types assigning to 'void (*)(void *)' from 'int (int *)'. void* -> integer -> void* rather than integer -> void* -> integer. How to tell which packages are held back due to phased updates, Identify those arcade games from a 1983 Brazilian music video. rev2023.3.3.43278. -1, Uggh. But the problem has still happened. pthread passes the argument as a void*. 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! 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. 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. rev2023.3.3.43278. 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). Safe downcast may be done with dynamic_cast. 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. Why does flowing off the end of a non-void function without returning a value not produce a compiler error? What does casting to void* does when passing arguments to variadic functions? Why is this sentence from The Great Gatsby grammatical? Are there tables of wastage rates for different fruit and veg? For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? reinterpret_cast<void *>(42)). To learn more, see our tips on writing great answers. If pointers are 64 bits and ints are 32 bits, an int is too small to hold a pointer value. 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. Asking for help, clarification, or responding to other answers. How do I align things in the following tabular environment? So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. Using Kolmogorov complexity to measure difficulty of problems? Converting a void* to an int is non-portable way that may work or may not! 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. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. what does it mean to convert int to void* or vice versa? ", "!"? And, most of these will not even work on gcc4. 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; B programing language is a language based on basic combined programming or a BCPL, and it is the precursor of the C programming language. However the actual code in question contains an explicit c-style cast to int. 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. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? To learn more, see our tips on writing great answers. reinterpret_cast is a type of casting operator used in C++. 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;.

Psychological Approach To Juvenile Delinquency, What Type Of Colony Was Pennsylvania, Why Does My Poop Smell Different After Covid, Articles C