Please tell me error: cast from 'void*' to 'int' loses precision, How Intuit democratizes AI development across teams through reusability. ../lib/odp-util.c:5489:33: note: expanded from macro 'SCAN_PUT_ATTR' You are just making it bigger by tricking the compiler and the ABI. There's no proper way to cast this to int in general case. Actions. How to tell which packages are held back due to phased updates, Identify those arcade games from a 1983 Brazilian music video. If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? 10) A prvalue of type pointer to void (possibly cv-qualified) can be converted to pointer to any object type. How to correctly cast a pointer to int in a 64-bit application? Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. 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? From the question I presume the OP does. 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. Fork 63. Find centralized, trusted content and collaborate around the technologies you use most. Not the answer you're looking for? While working with Threads in C, I'm facing the warning, "warning: cast to pointer from integer of different size". 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 mapping in pointer<->integer casts is implementation defined, but the intent was that if the pointer type is large enough and isn't forcefully aligned (, But that's different. This is flat out wrong. itch" "-I..\include\windows" "-Iinclude" "-I..\include" "-I..\datapath-windows\include" "-IC:\PTHREADS-BUILT\include" "-Xclang" "-fcolor-diagnostics" "-pipe" ../lib/odp-util.c:5658:9: note: expanded from macro 'SCAN_END_SINGLE' But then you need to cast your arguments inside your thread function which is quite unsafe cf. Create an account to follow your favorite communities and start taking part in conversations. Using Kolmogorov complexity to measure difficulty of problems? // 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. windows meson: cast to 'HANDLE' (aka 'void *') from smaller integer Asking for help, clarification, or responding to other answers. I'm trying to learn pthreads and thing that keeps bugging me is how do i really pass argument to the function. (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. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? 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 Since all pointers on 64-bit Windows are 64 bits, you are growing the data size from 32 bits backto 64 bits. Thank you all for your feedback. Can I tell police to wait and call a lawyer when served with a search warrant? What is "cast from integer to pointer of different size" warning? 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. 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". Your first example is risky because you have to be very careful about the object lifetimes. pthread passes the argument as a void*. Type Casting in C Language with Examples - Dot Net Tutorials byte -> short -> char -> int -> long -> float -> double. For a fairly recent compiler (that supports C99) you should not store or represent address as plain int value. I'm only guessing here, but I think what you are supposed to do is actually pass the address of the variable to the function. Java Type Casting. I usually have all automatic conversion warnings effective when developing in C, and I use explicit casting in order to suppress a specific . From that point on, you are dealing with 32 bits. To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. The correct answer is, if one does not mind losing data precision. int, bigint, smallint, and tinyint (Transact-SQL) - SQL Server A nit: in your version, the cast to void * is unnecessary. (i.e. Implicit conversions - cppreference.com I am an entry level C programmer. 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. 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. Number Type Cast | Qt Forum What does casting to void* does when passing arguments to variadic functions? 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? C - Type Casting - tutorialspoint.com What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? How to Cast a void* ponter to a char without a warning? Casting int to void* : r/C_Programming - reddit Anw, the project still build and run normally when i use Xcode 5.0 with iOS 7.0. 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). rev2023.3.3.43278. By clicking Sign up for GitHub, you agree to our terms of service and B language was designed to develop . reinterpret_cast conversion - cppreference.com *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 . In both cases, converting the pointer to an integer type that's too small to represent all pointer values is a bug. 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 Fix for objc/45925 Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? LLNL's tutorial is bad and they should feel bad. This solution is in accordance with INT18-C. Acidity of alcohols and basicity of amines. I am compiling this program in linux gcc compiler.. You think by casting it here that you are avoiding the problem! Find centralized, trusted content and collaborate around the technologies you use most. Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? Connect and share knowledge within a single location that is structured and easy to search. ../lib/odp-util.c:5601:9: note: expanded from macro 'SCAN_PUT' A cast converts an object or value from one type to another. I'm using cocos2d-x-2.2.2. ^~~~~~~~~~~~~~~~~~~~ This is known as implicit type casting or type promotion, compiler automatically converts smaller data type to larger data type. Press question mark to learn the rest of the keyboard shortcuts. The point is (probably) that the value passed to the thread is an integer value, not really a 'void *'. How do I set, clear, and toggle a single bit? 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 All character types are to be converted to an integer. *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 . If your standard library (even if it is not C99) happens to provide these types - use them. Click to see the query in the CodeQL repository. 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. You are correct, but cocos actually only uses that address as a unique id. windows meson: cast to smaller integer type 'unsigned long' from 'void @Artelius: Which, presumably, is exactly what Joshua did: A C++ reinterpret cast will not solve the problem. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. If int is no larger than pointer to void then one way to store the value is by simply copying the bytes: int i . Any help with this is appreciated. casting from int to void* and back to int - C / C++ Use returnPtr[j] = (void *) ((long)ptr + i); ). What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. The problem just occur with Xcode 5.1. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. /** Dynamically allocate a 2d (x*y) array of elements of size _size_ bytes. The only alternative is really to take time and fix all 64-bit code issues, of which there may be some non-trivial issues. error: comparison between pointer and integer ('int' and 'string' (aka 'char *')), CS50 Caesar program is working but check50 says it isn't. (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. 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; But assuming that it is, as long as the caller and the callee agree, you can do that sort of thing. You use the address-of operator & to do that. what does it mean to convert int to void* or vice versa? Getting Command /bin/sh failed with exit code 65 Error with Xcode 5.1 . Why is there a voltage on my HDMI and coaxial cables? Don't do that. 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. reinterpret_cast is a type of casting operator used in C++. It is commonly called a pointer to T and its type is T*. The proper way is to cast it to another pointer type. Making statements based on opinion; back them up with references or personal experience. Replacing broken pins/legs on a DIP IC package, How to handle a hobby that makes income in US. 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. Thanks Jonathan, I was thinking about my answer in another thread: AraK is correct, passing integers a pointers are not necessarily interchangeable. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. You can fix this error by replacing this line of code. Please unaccept the answer you have chosen as it is wrong (as the comments below it say) and will lead to bugs. Implementation-dependent. Why is this sentence from The Great Gatsby grammatical? Why does flowing off the end of a non-void function without returning a value not produce a compiler error? I have a two functions, one that returns an int, and one that takes a const void* as an argument. I cannot reverse my upvote of user384706's answer, but it's wrong. Note the difference between the type casting of a variable and type casting of a pointer. It solved my problem too. This example is noncompliant on an implementation where pointers are 64 bits and unsigned integers are 32 bits because the result of converting the 64-bit ptr cannot be represented in the 32-bit integer type. "clang" "-Ilib\libopenvswitch.a.p" "-Ilib" "-I..\lib" "-I." Cerror: cast to 'void *' from smaller integer type 'int' @Martin York: No, it doesn't depend on endiannness. Remembering to delete the pointer after use so that we don't leak. Find centralized, trusted content and collaborate around the technologies you use most. The program can be set in such a way to ask the user to inform the type of data and . 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. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Casting type void to uint8_t - Arduino Forum You are getting warnings due to casting a void* to a type of a different size. The result is implementation-defined and typically yields the numeric address of the byte in memory that the pointer pointers to. Then i can continue compiling. All float types are to be converted to double. this way I convert an int to a void* which is much better than converting a void* to an int. Not the answer you're looking for? But the problem has still happened. Yeah, the tutorial is doing it wrong. Does melting sea ices rises global sea level? What is the point of Thrower's Bandolier? See also this documentation.. From and Into are generally intended to be lossless, infalliable conversions.as on the other hand can discard data and lead to bugs in some situations, for example casting a u64 to a usize may truncate the value on a 32-bit host. This is a fine way to pass integers to new pthreads, if that is what you need. If any, how can the original function works without errors if we just ignore the warning. Bulk update symbol size units from mm to map units in rule-based symbology. 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]. static const void* M_OFFSET = (void*)64*1024; Since gcc compiles that you are performing arithmetic between void* and an int ( 1024 ). The dynamic_cast<>operator provides a way to check the actual type of a pointer to a polymorphic class. 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. However, you are also casting the result of this operation to (void*). So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. The reinterpret_cast makes the int the size of a pointer and the warning will stop. If the destination type is bool, this is a boolean conversion (see below). 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 ) If you cast an int pointer int, you might get back a different integer. ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' My code is all over the place now but I appreciate you all helping me on my journey to mastery! If the sizes are different then endianess comes into play. The bigint data type is intended for use when integer values might exceed the range that is supported by the int data type.. bigint fits between smallmoney and int in the data type precedence chart.. Does Counterspell prevent from any further spells being cast on a given turn? It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. SCAN_SINGLE("skb_priority(", uint32_t, u32, OVS_KEY_ATTR_PRIORITY); 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. How to get the error message from the error code returned by GetLastError()? Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. You can use a 64 bits integer instead howerver I usually use a function with the right prototype and I cast the function type : Update: Today, i download the latest version of cocos2d-x (cocos2d-x 2.2.3). BUT converting a pointer to void* and back again is well supported (everywhere). } SCAN_END_SINGLE(ATTR) Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Making statements based on opinion; back them up with references or personal experience. Why does setupterm terminate the program? 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 is memory reinterpretation - a completely unacceptable way to do what the OP is trying to do. Connect and share knowledge within a single location that is structured and easy to search. you can just change architecture to support 32 bit compilation by all below in in Build Settings. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? what happens when we typecast normal variable to void* or any pointer variable? However the actual code in question contains an explicit c-style cast to int. actually no, as int my be a smaller type than a pointer ;-) But, of course with int64_t it works fine.
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