@Artelius: Which, presumably, is exactly what Joshua did: A C++ reinterpret cast will not solve the problem. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~. Casting type void to uint8_t - Arduino Forum Click to see the query in the CodeQL repository. /** Dynamically allocate a 2d (x*y) array of elements of size _size_ bytes. That could create all kinds of trouble. So you could do this: Note: As sbi points out this would require a change on the OP call to create the thread. "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. Typecasting - Data Types - Language Basics - MQL4 Reference But I'm nitpicking .. This page was last modified on 12 February 2023, at 18:25. Bulk update symbol size units from mm to map units in rule-based symbology. This is flat out wrong. 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. [Solved] Error "Cast from pointer to smaller type 'int' | 9to5Answer GitHub. Taking the above declarations of A, D, ch of the . 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; Find centralized, trusted content and collaborate around the technologies you use most. Already on GitHub? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. A nit: in your version, the cast to void * is unnecessary. to the original pointer: The following type designates an unsigned integer type with the What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. The result is implementation-defined and typically yields the numeric address of the byte in memory that the pointer pointers to. 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. for (i=0, j=0; j A void pointer can be really useful if the programmer is not sure about the data type of data inputted by the end user.
How to Cast a void* ponter to a char without a warning? Here is my code: I already tried (void*)M_TABLE_SIZE but then I get an error that I cannot use the * operator. For example, if youwrite ((int*)ptr + 1), it will add 4 bytes to the pointer, because "ints" are 4 bytes each. 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. ), For those who are interested. If your standard library (even if it is not C99) happens to provide these types - use them. C / C++ Forums on Bytes. As for the stack, I've written a few libraries using pthreds, thus I don't agree that what you describe "is quite often the case". Asking for help, clarification, or responding to other answers. To learn more, see our tips on writing great answers. this way you won't get any warning. 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: I am using size_t here, because it is always having the same size as a pointer, no matter the platform. how to cascade 2d int array to 2d void pointer array? Do new devs get fired if they can't solve a certain bug? 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; Not the answer you're looking for? Why is this sentence from The Great Gatsby grammatical? you can just change architecture to support 32 bit compilation by all below in in Build Settings. On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. STR34-C. Cast characters to unsigned char before converting to larger Note:You might receive a runtime exception if the pointer contains a value unsuitable for the context. If you are going to pass the address you typically need to exert some more control over the lifetime of the object. Update: Today, i download the latest version of cocos2d-x (cocos2d-x 2.2.3). 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. Thanks for pointing that out. How can this new ban on drag possibly be considered constitutional? Yeah, the tutorial is doing it wrong. 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. Use #include to define it. To avoid truncating your pointer, cast it to a type of identical size. Example: int x=7, y=5; float z; z=x/y; /*Here the value of z is 1*/. It generally takes place when in an expression more than one data type is present. Making statements based on opinion; back them up with references or personal experience. Connect and share knowledge within a single location that is structured and easy to search. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. error: cast from pointer to smaller type 'unsigned int' loses information. "-D_FILE_OFFSET_BITS=64" "-Wall" "-Winvalid-pch" "-g" "-Wthread-safety" "-Wno-microsoft-enum-forward-reference" "-Wno-unused-function" "-Wno-sometimes-unini cast to void *' from smaller integer type 'int SCAN_PUT_ATTR(key, ATTR, skey, FUNC); Using printf with a pointer to float gives an error, Meaning of int (*) (int *) = 5 (or any integer value), Casting int to void* loses precision, and what is the solution in required cases, Acidity of alcohols and basicity of amines. Replacing broken pins/legs on a DIP IC package, How to handle a hobby that makes income in US. In this case, casting the pointer back to an integer is meaningless, because . B programing language is a language based on basic combined programming or a BCPL, and it is the precursor of the C programming language. For example, the main thread could wait for all of the other threads to end before terminating. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Setting a buffer of char* with intermediate casting to int*. casting from int to void* and back to int - C / C++ By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Why is this sentence from The Great Gatsby grammatical? And you can't pass a pointer to a stack based object from the other thread as it may no longer be valid. For example, if you want to store a 'long' value into a simple integer then you can type cast 'long' to 'int'. 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 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 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. Don't pass your int as a void*, pass a int* to your int, so you can cast the void* to an int* and copy the dereferenced pointer to your int. In the case of Widening Type Casting, the lower data type (having smaller size) is converted into the higher data type (having larger size). To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 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. Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. Where does this (supposedly) Gibson quote come from? 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. Implicit Type Conversion in C with Examples - GeeksforGeeks 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. I have a two functions, one that returns an int, and one that takes a const void* as an argument. Any help with this is appreciated. Instead of using a long cast, you should cast to size_t. I think the solution 3> should be the correct one. If the value is ever used as pointer again that will prove to be an extremely bad idea. Cast characters to unsigned char before converting to larger integer sizes Created by Robert Seacord, last modified by Jill Britton on Oct 03, 2022 Signed character data must be converted to unsigned char before being assigned or converted to a larger signed type. In such condition type conversion (type promotion) takes place to avoid loss of data. You may declare a const int variable and cast its reference to the void*. How to correctly type cast (void*)? - social.msdn.microsoft.com Acidity of alcohols and basicity of amines. 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. whether it was an actual problem is a different matter though. 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. Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. Therefore, you need to change it to long long instead of long in windows for 64 bits. C99 defines the types "intptr_t" and "uintptr_t" which do . long guarantees a pointer size on Linux on any machine. Find centralized, trusted content and collaborate around the technologies you use most. Making statements based on opinion; back them up with references or personal experience. Whats the grammar of "For those whose stories they are"? I guess the other important fact is that the cast operator has higher precedence that the multiplication operator. ^~~~~~~~~~~~~~~~~~~~ And in this context, it is very very very common to see programmers lazily type cast the. And then assign it to the double variable. actually no, as int my be a smaller type than a pointer ;-) But, of course with int64_t it works fine. What video game is Charlie playing in Poker Face S01E07? The result is the same as implicit conversion from the enum's underlying type to the destination type. Most answers just try to extract 32 useless bits out of the argument. How to make compiler not show int to void pointer cast warnings, incompatible pointer types assigning to 'void (*)(void *)' from 'int (int *)'. Star 675. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. You can use a 64 bits integer instead howerver I usually use a function with the right prototype and I cast the function type : If the sizes are different then endianess comes into play. Pull requests. 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;. How can this new ban on drag possibly be considered constitutional? 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 Pd = Pa; Similarly, Pc may be type cast to type int and assigned the value Pa. 1. This is not a conversion at all. You are right! Mutually exclusive execution using std::atomic? What is the correct method to cast an int to a void*? Hence there is no loss in data. Please tell me error: cast from 'void*' to 'int' loses precision, How Intuit democratizes AI development across teams through reusability. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? How do I force make/GCC to show me the commands? I personally upvoted this answer because by it's first line of text it helped me to understand the reason of this strange error message and what am I, poor idiot, doing :D. Not valid on Windows 64 - long is still 32-bit but pointers are 64-bit. What happens if you typecast as unsigned first? @Martin York: No, it doesn't depend on endiannness. 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. Thanks for contributing an answer to Stack Overflow! unsigned long call_fn = (unsigned long)FUNC; 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. A nit: in your version, the cast to void * is unnecessary. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin? [mst-vhost:vhost 5/52] drivers/block/virtio_blk.c:539:21: warning In simple example code like this it's very easy to convince yourself that there's no problem, but in more elaborate real-world scenarios it's very easy to make this mistake inadvertently. To learn more, see our tips on writing great answers. I have the following function and when I compile it under VS.NET 2005, the following compile warnings show up: Warning1warning C4311: 'type cast' : pointer truncation from 'void *' to 'long'c:\temp\testone\lib\utils.c56Warning2warning C4312: 'type cast' : conversion from 'unsigned long' to 'void *' of greater sizec:\temp\testone\lib\utils.c56, Code Snippet
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. 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. 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 with ids being an array of ints and touch being a pointer. 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. windows meson: cast to smaller integer type 'unsigned long' from 'void rev2023.3.3.43278. B Programming Language | What is the History and Concept? Find centralized, trusted content and collaborate around the technologies you use most. Once you manage to make this cast, then what?! An object pointer (including void*) or function pointer can be converted to an integer type using reinterpret_cast. 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. ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] Fork 63. But this code pass the normal variable .. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. what does it mean to convert int to void* or vice versa? How create a simple program using threads in C? From the question I presume the OP does. windows meson: cast to smaller integer type 'unsigned long' from 'void *'. Press question mark to learn the rest of the keyboard shortcuts. : iPhone Retina 4-inch 64-bit) is selected. Casting arguments inside the function is a lot safer. How to use Slater Type Orbitals as a basis functions in matrix method correctly? 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). arrays - I get the error: "cast to smaller integer type 'int' from You use the address-of operator & to do that. 471,961 Members | 900 Online. // 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. 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; 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). Netdev Archive on lore.kernel.org help / color / mirror / Atom feed * [mst-vhost:vhost 5/52] drivers/block/virtio_blk.c:539:21: warning: assignment to 'void *' from . To be honest, I think, clang is too restrictive here. To learn more, see our tips on writing great answers. "I think what you should do is actually pass the address of the variable to the function" Not necessarily. This method will not work on 64 bit Big Endian platform, so it unnecessarily breaks portability. The program can be set in such a way to ask the user to inform the type of data and . Getting Command /bin/sh failed with exit code 65 Error with Xcode 5.1 . return ((void **) returnPtr);} /* Matrix() */. -1, Uggh. B language was designed to develop . 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. The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. Type Casting in C Language with Examples - Dot Net Tutorials c - type casting integer to void* - Stack Overflow 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 the function had the correct signature you would not need to cast it explicitly. Mutually exclusive execution using std::atomic? The following program casts a double to an int. what happens when we typecast normal variable to void* or any pointer variable? 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. But the problem has still happened. 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). If the destination type is bool, this is a boolean conversion (see below). Note the difference between the type casting of a variable and type casting of a pointer. Can we typecast void into int? - Quora 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. Type Casting Of Pointers in C - Computer Notes 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 Now, what happens when I run it with the thread sanitizer? Replacing broken pins/legs on a DIP IC package, AC Op-amp integrator with DC Gain Control in LTspice. Why does flowing off the end of a non-void function without returning a value not produce a compiler error? We have to pass address of the variable to the function because in function definition argument is pointer variable. 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. No idea how it amassed 27 upvotes?! "clang" "-Ilib\libopenvswitch.a.p" "-Ilib" "-I..\lib" "-I." 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. } SCAN_END_SINGLE(ATTR) Is a PhD visitor considered as a visiting scholar. Bulk update symbol size units from mm to map units in rule-based symbology. Can Martian regolith be easily melted with microwaves? You cannot just cast the 32-bit variable to a pointer, because that pointer on a 64-bit machine is twice as long. Well occasionally send you account related emails. All float types are to be converted to double. For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? This is known as implicit type casting or type promotion, compiler automatically converts smaller data type to larger data type.
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