cast to void *' from smaller integer type 'int

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. Before I update Xcode, my project still can build and run normally with all devices. ^~~~~~~~~~~~~~~~~~~~~ For integer casts in specific, using into() signals that . reinterpret_cast is a type of casting operator used in C++. How do I check if a string represents a number (float or int)? Casting and type conversions - C# Programming Guide If you cast an int pointer int, you might get back a different integer. But I don't want to edit code in "EAGLView.mm" because it's a "library file". 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. If the original pointer value represents an address of a byte in memory that does not satisfy the alignment requirement of the target type, then the resulting pointer value is unspecified. How do I work around the GCC "error: cast from SourceLocation* to int loses precision" error when compiling cmockery.c? Most answers just try to extract 32 useless bits out of the argument. Does a summoned creature play immediately after being summoned by a ready action? It is done by the compiler on its own, without any external trigger from the user. } SCAN_END_SINGLE(ATTR) If any, how can the original function works without errors if we just ignore the warning. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @Artelius: Which, presumably, is exactly what Joshua did: A C++ reinterpret cast will not solve the problem. Floating-point conversions I understood, but that would introduce dynamic memory and ugly lifetime issues (an object allocated by one thread must be freed by some other) - all just to pass an. That could create all kinds of trouble. that any valid pointer to void can be converted to this type, then What is the point of Thrower's Bandolier? 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. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin?). converted back to pointer to void, and the result will compare equal this question. 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. And in this context, it is very very very common to see programmers lazily type cast the. lexborisov Modest Public. The reinterpret_cast makes the int the size of a pointer and the warning will stop. Projects. Making statements based on opinion; back them up with references or personal experience. 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. This allows you to reinterpret the void * as an int. To be honest, I think, clang is too restrictive here. It's an int type guaranteed to be big enough to contain a pointer. It generally takes place when in an expression more than one data type is present. In this case, casting the pointer back to an integer is meaningless, because . Bulk update symbol size units from mm to map units in rule-based symbology. Is it possible to create a concave light? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, error: cast from void* to int loses precision, cast to pointer from integer of different size, pthread code. 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 you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. 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; then converted back to pointer to void, and the result will compare Safe downcast may be done with dynamic_cast. 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. Casting int to void* loses precision, and what is the solution in required cases, c++: cast from "const variable*" to "uint32" loses precision, Recovering from a blunder I made while emailing a professor, Relation between transaction data and transaction id. a cast of which the programmer should be aware of what (s)he is doing. rev2023.3.3.43278. 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. B Programming Language | What is the History and Concept? Half your pointer will be garbage. warning C4311: 'type cast': pointer truncation from 'void *' to 'long' in ECPG test files. So you could do this: Note: As sbi points out this would require a change on the OP call to create the thread. Returns a value of type new-type. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? When is casting void pointer needed in C? 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). The problem just occur with Xcode 5.1. The preprocessor will replace your code by this: This is unlikely what you are trying to do. ^~~~~~~~~~~~~~~~~~~~~ } SCAN_END_SINGLE(ATTR) 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. If you are going to pass the address you typically need to exert some more control over the lifetime of the object. this way I convert an int to a void* which is much better than converting a void* to an int. static const void* M_OFFSET = (void*)64*1024; Since gcc compiles that you are performing arithmetic between void* and an int ( 1024 ). You can convert the values from one type to another explicitly using the cast operator as follows (type_name) expression Since gcc compiles that you are performing arithmetic between void* and an int (1024). You need to pass an actual pointer. This is why you got Error 1 C2036, from your post. 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. I am compiling this program in linux gcc compiler.. Can Martian regolith be easily melted with microwaves? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. ), For those who are interested. If your standard library (even if it is not C99) happens to provide these types - use them. 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). error: comparison between pointer and integer ('int' and 'string' (aka 'char *')), CS50 Caesar program is working but check50 says it isn't. The text was updated successfully, but these errors were encountered: 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. The main point is: a pointer has a platform dependent size. Put your define inside a bracket: without a problem. How to correctly cast a pointer to int in a 64-bit application? Yeah, the tutorial is doing it wrong. 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. ", "!"? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. whether it was an actual problem is a different matter though. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Dinesh: could you please 1) show us those. rev2023.3.3.43278. If you really need such trickery, then consider one of dedicated types, which are intptr_t and uintptr_t. int, bigint, smallint, and tinyint (Transact-SQL) - SQL Server 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. pthread create managing values generated in function (in c), Establishing TCP socket connection between PHP client and C server on Ubuntu. error: cast from pointer to smaller type 'unsigned int' loses sound/soc/codecs/tlv320aic32x4.c:1202:18: warning: cast to smaller How do I align things in the following tabular environment? Then i can continue compiling. 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. @LearnCocos2D: so, how can i "overcome" the error without editing any not-my-code or in-library-file lines? Mutually exclusive execution using std::atomic? Issues. All float types are to be converted to double. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Number Type Cast | Qt Forum I'm trying to learn pthreads and thing that keeps bugging me is how do i really pass argument to the function. this way you won't get any warning. To learn more, see our tips on writing great answers. Replacing broken pins/legs on a DIP IC package, How to handle a hobby that makes income in US. Is pthread_join a must when using pthread in linux? STR34-C. Cast characters to unsigned char before converting to larger For example, if you want to store a 'long' value into a simple integer then you can type cast 'long' to 'int'. How to make compiler not show int to void pointer cast warnings, incompatible pointer types assigning to 'void (*)(void *)' from 'int (int *)'. A nit: in your version, the cast to void * is unnecessary. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Offline ImPer Westermark over 11 years ago in reply to Andy Neil Except that you sometimes stores an integer in the pointer itself. @jackdoe: It's a waste of human life to write code that "you may need in the future". "-I.." "-Iinclude\openflow" "-I..\include\openflow" "-Iinclude\openvswitch" "-I..\include\openvsw 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]. Mutually exclusive execution using std::atomic? What is the difference between const int*, const int * const, and int const *? iphone - Error "Cast from pointer to smaller type 'int' loses The point is (probably) that the value passed to the thread is an integer value, not really a 'void *'. What video game is Charlie playing in Poker Face S01E07? void* -> integer -> void* rather than integer -> void* -> integer. This page was last modified on 12 February 2023, at 18:25. 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. Not the answer you're looking for? Why does flowing off the end of a non-void function without returning a value not produce a compiler error? 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 How to convert a factor to integer\numeric without loss of information? We have to pass address of the variable to the function because in function definition argument is pointer variable. ncdu: What's going on with this second size column? That's not a good idea if the original object (that was cast to void*) was an integer. long guarantees a pointer size on Linux on any machine. If this is the data to a thread procedure, then you quite commonly want to pass by value. Here, the Java first converts the int type data into the double type. Find centralized, trusted content and collaborate around the technologies you use most. ^~~~~~~~~~~~~~~~~~~~ should we also have a diagnostic for the (presumed) user error? Why is this sentence from The Great Gatsby grammatical? p-util.c.obj "-c" ../lib/odp-util.c 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. That's probably going to be true for most platforms you will ever encounter, but it's not a guarantee; it's implementation-dependent. On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. To cast such pointers to 32-bit types and vice versa special functions are used: void * Handle64ToHandle ( const void * POINTER_64 h ) void * POINTER_64 HandleToHandle64 ( const void *h ) long HandleToLong ( const void *h ) unsigned long HandleToUlong ( const void *h ) You should perform type conversion based on 64bit build system because the type "int" supports only -32768 ~ 32768. - the incident has nothing to do with me; can I use this this way? It is purely a compile-time directive which instructs the compiler to treat expression as if it had . Converting a pointer to an integer whose result cannot represented in the integer type is undefined behavior is C and prohibited in C++. Casting Pointers - IBM Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. In such condition type conversion (type promotion) takes place to avoid loss of data. @DietrichEpp can you explain what is race condition with using. 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. If your standard library (even if it is not C99) happens to provide these types - use them. Disconnect between goals and daily tasksIs it me, or the industry? It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~. And then assign it to the double variable. Connect and share knowledge within a single location that is structured and easy to search. 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. STR34-C. Identify those arcade games from a 1983 Brazilian music video. "I think what you should do is actually pass the address of the variable to the function" Not necessarily. Using indicator constraint with two variables. Keep in mind that thrArg should exist till the myFcn() uses it. How Intuit democratizes AI development across teams through reusability. The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. You may declare a const int variable and cast its reference to the void*. Based on the design of this function, which modification is right. Whats the grammar of "For those whose stories they are"? For example, the main thread could wait for all of the other threads to end before terminating. 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. C - Type Casting - tutorialspoint.com Thanks for contributing an answer to Stack Overflow! Error while setting app icon and launch image in xcode 5.1. Cast unsigned char (uint8 *) pointer to unsigned long (uint32 *) pointer You could use this code, and it would do the same thing as casting ptr to (char*). What you do here is undefined behavior, and undefined behavior of very practical sort. Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? (void *)i Error: cast to 'void *' from smaller integer type 'int'. You can use any other pointer, or you can use (size_t), which is 64 bits. Anw, the project still build and run normally when i use Xcode 5.0 with iOS 7.0. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Therefore, you need to change it to long long instead of long in windows for 64 bits. Casting arguments inside the function is a lot safer. What does it mean to convert int to void* or vice versa? Functions return bigint only if the parameter expression is a bigint data type. 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. Surely the solution is to change the type of ids from int to type that is sufficiently large to hold a pointer. A cast is a way of explicitly informing the compiler that you intend to make the conversion and that you are aware that data loss might occur, or the cast may fail at run time. A missing cast in the new fast > enumeration code. This method will not work on 64 bit Big Endian platform, so it unnecessarily breaks portability. Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul *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 . Create an account to follow your favorite communities and start taking part in conversations. This is not even remotely "the correct answer". But assuming that it is, as long as the caller and the callee agree, you can do that sort of thing. The text was updated successfully, but these errors were encountered: You signed in with another tab or window. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? 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! What happens if you typecast as unsigned first? Implicit conversions - cppreference.com This forum has migrated to Microsoft Q&A. While working with Threads in C, I'm facing the warning, "warning: cast to pointer from integer of different size". So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. : iPhone Retina 4-inch 64-bit) is selected. 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. Connect and share knowledge within a single location that is structured and easy to search. Does Counterspell prevent from any further spells being cast on a given turn? No sense in writing a few dozen lines of extra code just to get a bunch of numbered threads. The correct answer is, if one does not mind losing data precision. This answer is incorrect for the reasons that have already been mentioned in the comment of, Error "Cast from pointer to smaller type 'int' loses information" in EAGLView.mm when update Xcode to 5.1 (5B130a), http://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models, http://stackoverflow.com/questions/18913906/xcode-5-and-ios-7-architecture-and-valid-architectures, How Intuit democratizes AI development across teams through reusability. Thank you all for your feedback. As was pointed out by Martin, this presumes that sizeof(void*)>=sizeof(int). I don't see how anything bad can happen . As Ferruccio said, int must be replaced with intptr_t to make the program meaningful. SCAN_PUT(ATTR, NULL); There is no "correct" way to store a 64-bit pointer in an 32-bit integer. How to correctly cast a pointer to int in a 64-bit application? The result is the same as implicit conversion from the enum's underlying type to the destination type. Already on GitHub? So reinterpret_cast has casted it to long type and then static_cast safely casts long to int, if you are ready do truncte the data. I assumed that gcc makes a 65536 out of my define, but I was wrong. Clang warnings for an invalid casting? - The FreeBSD Forums ERROR: incompatible integer to pointer conversion assigning to 'string' (aka 'char *') from 'int', error: cast to 'string' (aka 'char *') from smaller integer type 'int' [-Werror,-Wint-to-pointer-cast], error: incompatible integer to pointer conversion assigning to 'string' (aka 'char *') from 'int' C, warning: initialization of 'unsigned char' from 'uint8_t *' {aka 'unsigned char *'} makes integer from pointer without a cast [-Wint-conversion], Minimising the environmental effects of my dyson brain. How do I force make/GCC to show me the commands? Types - D Programming Language This is what the second warning is telling you. How can this new ban on drag possibly be considered constitutional? Is it possible to create a concave light? equal to the original pointer: First you are using a define, which is not a variable. */void **MatrixIB (unsigned long x, unsigned long y, int size){ void *ptr; void **returnPtr; register unsigned long i, j; This is a fine way to pass integers to new pthreads, if that is what you need. Visit Microsoft Q&A to post new questions. 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;. for saving RAM), use union, and make sure, if the mem address is treated as an int only if you know it was last set as an int. This is an old C callback mechanism so you can't change that. you can just change architecture to support 32 bit compilation by all below in in Build Settings. Does Counterspell prevent from any further spells being cast on a given turn? Only the following conversions can be done with static_cast, except when such conversions would cast away constness or volatility. 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. I agree passing a dynamically allocated pointer is fine (and I think the best way). Asking for help, clarification, or responding to other answers. How to use Slater Type Orbitals as a basis functions in matrix method correctly? Converting a void* to an int is non-portable way that may work or may not! Connect and share knowledge within a single location that is structured and easy to search. 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. [Solved] Properly casting a `void*` to an integer in C++ 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. "-D_FILE_OFFSET_BITS=64" "-Wall" "-Winvalid-pch" "-g" "-Wthread-safety" "-Wno-microsoft-enum-forward-reference" "-Wno-unused-function" "-Wno-sometimes-unini Type Casting in C Language with Examples - Dot Net Tutorials If the sizes are different then endianess comes into play. a is of type int[4], which can be implicitly cast to int* (ie, a pointer to an int) &a is of type int(*)[4] (ie: a pointer to an array of 4 ints). AC Op-amp integrator with DC Gain Control in LTspice. windows meson: cast to smaller integer type 'unsigned long' from 'void *'. 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. For example, if youwrite ((int*)ptr + 1), it will add 4 bytes to the pointer, because "ints" are 4 bytes each. Connect and share knowledge within a single location that is structured and easy to search. rev2023.3.3.43278. B programing language is a language based on basic combined programming or a BCPL, and it is the precursor of the C programming language. It is easier to understand and write than any other assembly language. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project?