You need to pass an actual pointer. If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. What is the purpose of non-series Shimano components? void* -> integer -> void* rather than integer -> void* -> integer. Can I tell police to wait and call a lawyer when served with a search warrant? 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. You should perform type conversion based on 64bit build system because the type "int" supports only -32768 ~ 32768. 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. What is the purpose of non-series Shimano components? 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; 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). *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 . you can just change architecture to support 32 bit compilation by all below in in Build Settings. AC Op-amp integrator with DC Gain Control in LTspice. Safe downcast may be done with dynamic_cast. As with all cast expressions, the result is: Two objects a and b are pointer-interconvertible if: static_cast may also be used to disambiguate function overloads by performing a function-to-pointer conversion to specific type, as in. I think the solution 3> should be the correct one. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Converting a pointer to an integer whose result cannot represented in the integer type is undefined behavior is C and prohibited in C++. ^~~~~~~~~~~~~~~~~~~ The difference between a and &a is the type. I would create a structure and pass that as void* to pthread_create. ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' What is the correct method to cast an int to a void*? You can fix this error by replacing this line of code. Types - D 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. Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? Casting type int to const void* - C / C++ If this is the data to a thread procedure, then you quite commonly want to pass by value. 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. ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] Thus as a result it may be less error prone to generate a pointer dynamcially and use that. whether it was an actual problem is a different matter though. For integer casts in specific, using into() signals that . 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). You could use this code, and it would do the same thing as casting ptr to (char*). Narrowing Casting (manually) - converting a larger type to a . 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. Please help me compile Chez Scheme. Please unaccept the answer you have chosen as it is wrong (as the comments below it say) and will lead to bugs. *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 . 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. Why does setupterm terminate the program? 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. Bulk update symbol size units from mm to map units in rule-based symbology. ), For those who are interested. ../lib/odp-util.c:5658:9: note: expanded from macro 'SCAN_END_SINGLE' Hence there is no loss in data. The preprocesor absolutely will not perform arithmetic. Thanks Jonathan, I was thinking about my answer in another thread: AraK is correct, passing integers a pointers are not necessarily interchangeable. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. [] ExplanatioUnlike static_cast, but like const_cast, the reinterpret_cast expression does not compile to any CPU instructions (except when converting between integers and pointers or on obscure architectures where pointer representation depends on its type). But the problem has still happened. 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). To avoid truncating your pointer, cast it to a type of identical size. In such condition type conversion (type promotion) takes place to avoid loss of data. Keep in mind that thrArg should exist till the myFcn() uses it. This is a fine way to pass integers to new pthreads, if that is what you need. Does melting sea ices rises global sea level? What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? 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. 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. Just edited. An open (void) pointer can hold a pointer of any type. 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. However even though their types are different, the address is going to be the same. "After the incident", I started to be more careful not to trip over things. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. I need to cast the int from the first function so that I can use it as an argument for the second function. reinterpret_cast conversion - cppreference.com equal to the original pointer: First you are using a define, which is not a variable. (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. To learn more, see our tips on writing great answers. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin?). In such a case the programmer can use a void pointer to point to the location of the unknown data type. Clang warnings for an invalid casting? - The FreeBSD Forums To learn more, see our tips on writing great answers. Why is there a voltage on my HDMI and coaxial cables? 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; If your standard library (even if it is not C99) happens to provide these types - use them. How to correctly type cast (void*)? - social.msdn.microsoft.com Thank you all for your feedback. 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. What is the point of Thrower's Bandolier? 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 How do I check if a string represents a number (float or int)? It solved my problem too. 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. ", "? property that any valid pointer to void can be converted to this type, Otherwise, if the original pointer value points to an object a, and there is an object b of the . Basically its a better version of (void *)i. I'm using cocos2d-x-2.2.2. 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. Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. Don't do that. How to convert a factor to integer\numeric without loss of information? The most general answer is - in no way. Using Kolmogorov complexity to measure difficulty of problems? Mutually exclusive execution using std::atomic? Terrible solution. Making statements based on opinion; back them up with references or personal experience. Does Counterspell prevent from any further spells being cast on a given turn? @kshegunov said in Number Type Cast: const void * x; int y = int (x); compiles just fine. @Shahbaz you could but I will not suggest to a C newbie to use globals. BUT converting a pointer to void* and back again is well supported (everywhere). In both cases, converting the pointer to an integer type that's too small to represent all pointer values is a bug. static_cast conversion - cppreference.com 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. Usually that means the pointer is allocated with. SCAN_PUT_ATTR(key, ATTR, skey, FUNC); 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. Implicit Type Conversion is also known as 'automatic type conversion'. . It is easier to understand and write than any other assembly language. This allows you to reinterpret the void * as an int. Why do small African island nations perform better than African continental nations, considering democracy and human development? And you can't pass a pointer to a stack based object from the other thread as it may no longer be valid. I am an entry level C programmer. Remarks. Can we typecast void into int? - Quora Thanks for contributing an answer to Stack Overflow! Cast a smaller integer to a larger integer - community - The Rust For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? But then you need to cast your arguments inside your thread function which is quite unsafe cf. C - Type Casting - tutorialspoint.com This is why you got Error 1 C2036, from your post. with ids being an array of ints and touch being a pointer. Bulk update symbol size units from mm to map units in rule-based symbology. Therefore, you need to change it to long long instead of long in windows for 64 bits. You can only do this if you use a synchronization primitive to ensure that there is no race condition. For example, if youwrite ((int*)ptr + 1), it will add 4 bytes to the pointer, because "ints" are 4 bytes each. 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 - How to cast an integer to void pointer? - Stack Overflow Implicit conversions - cppreference.com Find centralized, trusted content and collaborate around the technologies you use most. SCAN_PUT(ATTR, NULL); Create an account to follow your favorite communities and start taking part in conversations. The result is implementation-defined and typically yields the numeric address of the byte in memory that the pointer pointers to. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. The problem was there before, you just are being notified of it. Note:You might receive a runtime exception if the pointer contains a value unsuitable for the context. All float types are to be converted to double. 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. Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul rev2023.3.3.43278. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. use $(ARCHS_STANDARD_32_BIT) at Architecture instead of $(ARCHS_STANDARD). There is no "correct" way to store a 64-bit pointer in an 32-bit integer. Converting one datatype into another is known as type casting or, type-conversion. There exist two main syntaxes for generic type-casting: functional and c-like: 1 2 3 4 double x = 10.3; int y; y = int (x); // functional notation y = (int) x; // c-like cast notation The functionality of these generic forms of type-casting is enough for most needs with fundamental data types. 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 To be honest, I think, clang is too restrictive here. 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 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. c - Cast int to void* - Stack Overflow The problem is not with casting, but with the target type loosing half of the pointer. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? 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. I wish that you write those answer first than the explanation. How to Cast a void* ponter to a char without a warning? Can Martian regolith be easily melted with microwaves? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. For example, the main thread could wait for all of the other threads to end before terminating. How Intuit democratizes AI development across teams through reusability. 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). Mutually exclusive execution using std::atomic? 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. - the incident has nothing to do with me; can I use this this way? Visit Microsoft Q&A to post new questions. Connect and share knowledge within a single location that is structured and easy to search. How to use Slater Type Orbitals as a basis functions in matrix method correctly? SCAN_PUT(ATTR, NULL); You are right! Use of Void pointers in C programming language What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? A nit: in your version, the cast to void * is unnecessary. Whats the grammar of "For those whose stories they are"? lexborisov Modest Public. Already on GitHub? 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;. Cast Operations - Oracle 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. How to correctly cast a pointer to int in a 64-bit application? Is it possible to create a concave light? To learn more, see our tips on writing great answers. rev2023.3.3.43278. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence?