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. 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.. Did i have to face to unexpected runtime issues, i guess not, i've found another discussion on this -. If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. 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 But the problem has still happened. Why does setupterm terminate the program? And, most of these will not even work on gcc4. Why does Mister Mxyzptlk need to have a weakness in the comics? Bulk update symbol size units from mm to map units in rule-based symbology. Thanks for contributing an answer to Stack Overflow! If this is the data to a thread procedure, then you quite commonly want to pass by value. SCAN_PUT_ATTR(key, ATTR, skey, FUNC); By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. this way you won't get any warning.
How to Cast a void* ponter to a char without a warning? 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. No idea how it amassed 27 upvotes?! Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore.
For example, the main thread could wait for all of the other threads to end before terminating.
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static_cast conversion - cppreference.com Using Kolmogorov complexity to measure difficulty of problems? And in the function you get the value of the pointer by using the dereference operator *: Please read why glib provide macros for this kind of conversions, there's no need to repeat the text here.
Re: [PATCH, PR 53001] Re: Patch to split out new warning flag for use $(ARCHS_STANDARD_32_BIT) at Architecture instead of $(ARCHS_STANDARD). reinterpret_cast<void *>(42)). 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. For a fairly recent compiler (that supports C99) you should not store or represent address as plain int value. The difference between the phonemes /p/ and /b/ in Japanese. Not the answer you're looking for? . rev2023.3.3.43278. Why do academics stay as adjuncts for years rather than move around? Why is this sentence from The Great Gatsby grammatical?
Casting int to void* : r/C_Programming - reddit If not, check the pointer size on your platform, define these typedefs accordingly yourself and use them. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. In Java, there are two types of casting: Widening Casting (automatically) - converting a smaller type to a larger type size.
[Solved] Properly casting a `void*` to an integer in C++ How to convert a factor to integer\numeric without loss of information? Issues. However even though their types are different, the address is going to be the same. Maybe you can try this too. 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. The problem was there before, you just are being notified of it. 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. This is not a conversion at all. eg. Where does this (supposedly) Gibson quote come from? Floating-point conversions By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. ncdu: What's going on with this second size column? Linear regulator thermal information missing in datasheet. Yeah, the tutorial is doing it wrong. Windows has 32 bit long only on 64 bit as well. Find centralized, trusted content and collaborate around the technologies you use most. 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. Why do small African island nations perform better than African continental nations, considering democracy and human development? To learn more, see our tips on writing great answers. Api says this is how i should create thread: So if I want to pass an int what I think I should do is: The second example assumes that a pointer is wide enough to store an int. SCAN_SINGLE("skb_priority(", uint32_t, u32, OVS_KEY_ATTR_PRIORITY);
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. static_cast on the other hand should deny your stripping away the const qualifier. There are ways to prevent this: pass a dynamic allocated argument if your not the passing thread is not static or if your argument is a local variable, otherwise there is no issue. That's not a good idea if the original object (that was cast to void*) was an integer. The following behavior-changing defect reports were applied retroactively to previously published C++ standards. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant?
Casting Pointers - IBM Example: int x=7, y=5; float z; z=x/y; /*Here the value of z is 1*/. You cannot just cast the 32-bit variable to a pointer, because that pointer on a 64-bit machine is twice as long. I'm trying to learn pthreads and thing that keeps bugging me is how do i really pass argument to the function. pthread passes the argument as a void*. And then assign it to the double variable. @Martin York: No, it doesn't depend on endiannness. 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 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. Thanks. Please tell me error: cast from 'void*' to 'int' loses precision, How Intuit democratizes AI development across teams through reusability. I would create a structure and pass that as void* to pthread_create. Terrible solution.
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 On all of them int is 32bit, not 16bit. 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. reinterpret_cast is a type of casting operator used in C++. Most answers just try to extract 32 useless bits out of the argument. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin?). -1, Uggh. 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. I wish that you write those answer first than the explanation. LLNL's tutorial is bad and they should feel bad. windows meson: cast to smaller integer type 'unsigned long' from 'void *'. How to make compiler not show int to void pointer cast warnings, incompatible pointer types assigning to 'void (*)(void *)' from 'int (int *)'. Hence there is no loss in data. How Intuit democratizes AI development across teams through reusability. If you really need such trickery, then consider one of dedicated types, which are intptr_t and uintptr_t. It is done by the compiler on its own, without any external trigger from the user. This is a fine way to pass integers to new pthreads, if that is what you need. You should perform type conversion based on 64bit build system because the type "int" supports only -32768 ~ 32768. To learn more, see our tips on writing great answers. This is what the second warning is telling you.
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.
Cast a smaller integer to a larger integer - community - The Rust 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. warning C4311: 'type cast': pointer truncation from 'void *' to 'long' in ECPG test files. Just edited. But then you need to cast your arguments inside your thread function which is quite unsafe cf. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Otherwise, if the original pointer value points to an object a, and there is an object b of the . Is pthread_join a must when using pthread in linux? 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". Getting Command /bin/sh failed with exit code 65 Error with Xcode 5.1 . There is absolutely not gurantee that sizeof(int) <= sizeof(void*). SCAN_SINGLE("skb_priority(", uint32_t, u32, OVS_KEY_ATTR_PRIORITY); Making statements based on opinion; back them up with references or personal experience. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? Don't do that. Such pointers can be stored in 32-bit data types (for instance, int, DWORD). Keep in mind that thrArg should exist till the myFcn() uses it. Does Counterspell prevent from any further spells being cast on a given turn? The code ((void*)ptr + 1) does not work, because the compiler has no idea what size "void" is, and therefore doesn't know how many bytes to add. XCode 5.1 is change all architecture to 64 bit. How Intuit democratizes AI development across teams through reusability. In such condition type conversion (type promotion) takes place to avoid loss of data.
arrays - I get the error: "cast to smaller integer type 'int' from Why is this sentence from The Great Gatsby grammatical? This allows you to reinterpret the void * as an int. What is the difference between const int*, const int * const, and int const *? LLNL's tutorial is bad and they should feel bad. Wrong. how to cascade 2d int array to 2d void pointer array? 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. 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 information. However, I believe that even if the define was for the "65536", it would not be what @kaetzacoatl wanted. All character types are to be converted to an integer.
windows meson: cast to 'HANDLE' (aka 'void *') from smaller integer It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. If it's anything like cocos2d-iphone v2.x and just based on this slice of code in a core class I wager it's safe to say that cocos2d-x 2.x also is not compatible with 64 bit code, and you can expect all kinds of issues (not just compile-time but also runtime). This is not even remotely "the correct answer". And when assigning to a void pointer, all type information is lost. Mutually exclusive execution using std::atomic? 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 you are planning to use pthreads and you are planning to pass the pass function to pthread_create, you have to malloc/free the arguments you are planning to use (even if the threaded function just need a single int). Replacing broken pins/legs on a DIP IC package, AC Op-amp integrator with DC Gain Control in LTspice. I usually have all automatic conversion warnings effective when developing in C, and I use explicit casting in order to suppress a specific . rev2023.3.3.43278. 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).