cast to void *' from smaller integer type 'int

I agree passing a dynamically allocated pointer is fine (and I think the best way). How Intuit democratizes AI development across teams through reusability. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? @Artelius: Which, presumably, is exactly what Joshua did: A C++ reinterpret cast will not solve the problem. That could create all kinds of trouble. and how to print the thread id of 2d array argument? ^~~~~~~~~~~~~~~~~~~~ C / C++ Forums on Bytes. 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. The reinterpret_cast makes the int the size of a pointer and the warning will stop. A cast specifies a conversion from one type to another. Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. If the sizes are different then endianess comes into play. @DavidHeffernan I rephrased that sentence a little. You need to pass an actual pointer. The result is the same as implicit conversion from the enum's underlying type to the destination type. This returns the first 32 bits of the pointer which may be the top or the bottom depending on big versus little endian, as comment #2 said. Offline ImPer Westermark over 11 years ago in reply to Andy Neil Except that you sometimes stores an integer in the pointer itself. what happens when we typecast normal variable to void* or any pointer variable? ^~~~~~~~~~~~~~~~~~~~ Asking for help, clarification, or responding to other answers. Does Counterspell prevent from any further spells being cast on a given turn? To be honest, I think, clang is too restrictive here. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? Or, they are all wrong. 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). It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? reinterpret_cast is a type of casting operator used in C++. A nit: in your version, the cast to void * is unnecessary. Whats the grammar of "For those whose stories they are"? I don't see how anything bad can happen . 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;. No sense in writing a few dozen lines of extra code just to get a bunch of numbered threads. Find centralized, trusted content and collaborate around the technologies you use most. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin? 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. ^~~~~~~~~~~~~~~~~~~~~ Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. A nit: in your version, the cast to void * is unnecessary. For the remaining integral types, the result is the value of the enum if it can be represented by the target type and unspecified otherwise. @BlueMoon Thanks a lot! error: comparison between pointer and integer ('int' and 'string' (aka 'char *')), CS50 Caesar program is working but check50 says it isn't. The OP wanted to convert a pointer value to a int value, instead, most the answers, one way or the other, tried to wrongly convert the content of arg points to to a int value. Recovering from a blunder I made while emailing a professor. Bulk update symbol size units from mm to map units in rule-based symbology. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. As a result of the integer division 3/2 we get the value 1, which is of the int type. Please help me compile Chez Scheme. An object pointer (including void*) or function pointer can be converted to an integer type using reinterpret_cast. you can just change architecture to support 32 bit compilation by all below in in Build Settings. Again, all of the answers above missed the point badly. Why do academics stay as adjuncts for years rather than move around? ../lib/odp-util.c:5603:13: note: expanded from macro 'SCAN_PUT' 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 correctly cast a pointer to int in a 64-bit application? In this case, casting the pointer back to an integer is meaningless, because . Please unaccept the answer you have chosen as it is wrong (as the comments below it say) and will lead to bugs. What is the point of Thrower's Bandolier? To learn more, see our tips on writing great answers. 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. ncdu: What's going on with this second size column? SCAN_PUT(ATTR, NULL); Implicit Type Conversion is also known as 'automatic type conversion'. I recall there was a TreeNode(int) early on prior to 1.0 release I can't remember why I removed it, if I should felt it was easy enough to cast to (void*) or if it was because it created type inference conflict at the call site. to your account, [87/252] Compiling C object lib/libopenvswitch.a.p/odp-util.c.obj How to convert a factor to integer\numeric without loss of information? On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. Thanks for contributing an answer to Stack Overflow! A cast converts an object or value from one type to another. to the original pointer: The following type designates an unsigned integer type with the Replacing broken pins/legs on a DIP IC package, How to handle a hobby that makes income in US. If you are going to pass the address you typically need to exert some more control over the lifetime of the object. Well it does this because you are converting a 64 bits pointer to an 32 bits integer so you loose information. Difficulties with estimation of epsilon-delta limit proof. Why is this sentence from The Great Gatsby grammatical? Why do small African island nations perform better than African continental nations, considering democracy and human development? The subreddit for the C programming language, Press J to jump to the feed. I need to cast the int from the first function so that I can use it as an argument for the second function. 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. How to notate a grace note at the start of a bar with lilypond? The most general answer is - in no way. You could use this code, and it would do the same thing as casting ptr to (char*). Surely the solution is to change the type of ids from int to type that is sufficiently large to hold a pointer. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. what does it mean to convert int to void* or vice versa? SQL Server does not automatically promote . windows meson: cast to smaller integer type 'unsigned long' from 'void *'. 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. If you really need such trickery, then consider one of dedicated types, which are intptr_t and uintptr_t. Since the 'size' argument for your function is the number of bytes each element in the array needs, I think casting the pointerto (char*) is appropriate. The problem just occur with Xcode 5.1. 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. 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. How to use Slater Type Orbitals as a basis functions in matrix method correctly? Don't do that. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? But assuming that it is, as long as the caller and the callee agree, you can do that sort of thing. How to use Slater Type Orbitals as a basis functions in matrix method correctly? Such pointers can be stored in 32-bit data types (for instance, int, DWORD). property that any valid pointer to void can be converted to this type, For integer casts in specific, using into() signals that . I am an entry level C programmer. As was pointed out by Martin, this presumes that sizeof(void*)>=sizeof(int). The preprocessor will replace your code by this: This is unlikely what you are trying to do. This is not a conversion at all. p-util.c.obj "-c" ../lib/odp-util.c 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. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. It is purely a compile-time directive which instructs the compiler to treat expression as if it had . But the problem has still happened. And then assign it to the double variable. If the destination type is bool, this is a boolean conversion (see below). By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. - the incident has nothing to do with me; can I use this this way? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? But I'm nitpicking .. What you do here is undefined behavior, and undefined behavior of very practical sort. This solution is in accordance with INT18-C. Did i have to face to unexpected runtime issues, i guess not, i've found another discussion on this -. 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. How to get the error message from the error code returned by GetLastError()? Star 675. Casting an open pointer to other pointer types and casting other pointer types to an open pointer does not result in a compile time error. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. In Java, there are two types of casting: Widening Casting (automatically) - converting a smaller type to a larger type size. If you cast an int pointer int, you might get back a different integer. vegan) just to try it, does this inconvenience the caterers and staff? The int data type is the primary integer data type in SQL Server. This will only compile if the destination type is long enough. You use the address-of operator & to do that. 7.1 New Cast Operations The C++ standard defines new cast operations that provide finer control than previous cast operations. This will get you a pointer from a 32 bit offset: A function pointer is incompatible to void* (and any other non function pointer). 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. From the question I presume the OP does. 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). Thanks for contributing an answer to Stack Overflow! Infact I know several systems where that does not hold. The high-order 9 bits of the number are used to hold a flag value, and the result is converted back into a pointer. [] 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). Pd = Pa; Similarly, Pc may be type cast to type int and assigned the value Pa. 1. 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.." "-Iinclude\openflow" "-I..\include\openflow" "-Iinclude\openvswitch" "-I..\include\openvsw 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)). If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. 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]. No idea how it amassed 27 upvotes?! Just re-enforcing the old behavior of Xcode 5.0 and earlier versions, that already cut away parts of the address by casting it to int, won't introduce any new bugs and avoids the need to learn and understand lots of implementation-internal cocos code. Do new devs get fired if they can't solve a certain bug? should we also have a diagnostic for the (presumed) user error? ncdu: What's going on with this second size column? @Martin York: No, it doesn't depend on endiannness. Anw, the project still build and run normally when i use Xcode 5.0 with iOS 7.0. */void **MatrixIB (unsigned long x, unsigned long y, int size){ void *ptr; void **returnPtr; register unsigned long i, j; BUT converting a pointer to void* and back again is well supported (everywhere). There's no proper way to cast this to int in general case. 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. If you preorder a special airline meal (e.g. Thanks for contributing an answer to Stack Overflow! A void pointer can be really useful if the programmer is not sure about the data type of data inputted by the end user. this way you won't get any warning. Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul Find centralized, trusted content and collaborate around the technologies you use most. Maybe you can try this too. 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). Note that it's not guaranteed that casting an, Generally this kind of type casting does not lead to any concern as long as the addresses are encoded using the same length as the "variable type" (. this way I convert an int to a void* which is much better than converting a void* to an int. [that could be a TODO - not to delay solving the ICE]. 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 To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. pthread passes the argument as a void*. 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.



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