Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. But I don't want to edit code in "EAGLView.mm" because it's a "library file". Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Xcode 5 and iOS 7: Architecture and Valid architectures, xcode build error: Semantic issue cast from pointer to smaller type 'int' loses information, Issues in handling touches on subviews(uiviews) in UIScrollView, Architecture linking error after Xcode 5.1 upgrade, iOS 7.1 gives error after updating to Xcode 5.1, Linker error in Xcode 5.1 with cocos2d-x 3 beta 2. Whats the grammar of "For those whose stories they are"? The correct answer is, if one does not mind losing data precision. (void *)i Error: cast to 'void *' from smaller integer type 'int'. In such a case the programmer can use a void pointer to point to the location of the unknown data type. 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" (. It's an int type guaranteed to be big enough to contain a pointer. Use #include to define it. (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. Bulk update symbol size units from mm to map units in rule-based symbology. 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. However, I believe that even if the define was for the "65536", it would not be what @kaetzacoatl wanted. It generally takes place when in an expression more than one data type is present. It solved my problem too. use $(ARCHS_STANDARD_32_BIT) at Architecture instead of $(ARCHS_STANDARD). vegan) just to try it, does this inconvenience the caterers and staff? If int is no larger than pointer to void then one way to store the value is by simply copying the bytes: int i . In C (int)b is called an explicit conversion, i.e. Put your define inside a bracket: without a problem. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Not the answer you're looking for? equal to the original pointer: First you are using a define, which is not a variable. 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. BUT converting a pointer to void* and back again is well supported (everywhere). ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~. SCAN_SINGLE("skb_priority(", uint32_t, u32, OVS_KEY_ATTR_PRIORITY); ../lib/odp-util.c:5489:33: note: expanded from macro 'SCAN_PUT_ATTR' Why did Ukraine abstain from the UNHRC vote on China? byte -> short -> char -> int -> long -> float -> double. error: comparison between pointer and integer ('int' and 'string' (aka 'char *')), CS50 Caesar program is working but check50 says it isn't. 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. static const void* M_OFFSET = (void*)64*1024; Since gcc compiles that you are performing arithmetic between void* and an int ( 1024 ). To learn more, see our tips on writing great answers. You are right! *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 . The following behavior-changing defect reports were applied retroactively to previously published C++ standards. I think the solution 3> should be the correct one. C / C++ Forums on Bytes. How can this new ban on drag possibly be considered constitutional? Passing arguments to pthread_create - invalid conversion from void(*)() to void(*)(void*). Can Martian regolith be easily melted with microwaves? Safe downcast may be done with dynamic_cast. You are getting warnings due to casting a void* to a type of a different size. Put your define inside a bracket: #define M_TABLE_SIZE (64*1024) Now, you can do: static const void* M_OFFSET = (void*) M_TABLE_SIZE; without a problem. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Linear regulator thermal information missing in datasheet. 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. Not the answer you're looking for? 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. 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. However even though their types are different, the address is going to be the same. You need to cast the void* pointer to a char* pointer - and then dereference that char* pointer to give you the char that it points to! Using indicator constraint with two variables. Mutually exclusive execution using std::atomic? Actions. Implementation-dependent. Bulk update symbol size units from mm to map units in rule-based symbology. 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.. what happens when we typecast normal variable to void* or any pointer variable? For example, the main thread could wait for all of the other threads to end before terminating. This page was last modified on 12 February 2023, at 18:25. rev2023.3.3.43278. The difference between the phonemes /p/ and /b/ in Japanese, Styling contours by colour and by line thickness in QGIS. What video game is Charlie playing in Poker Face S01E07? x is a local variable and its lifetime ends as soon as control leaves the scope it was defined in. how to cascade 2d int array to 2d void pointer array? 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. ^~~~~~~~~~~~~~~~~~~~ What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? -1, Uggh. Why is there a voltage on my HDMI and coaxial cables? On most platforms pointers and longs are the same size, but ints and pointers often are not the same size on 64bit platforms. How do I force make/GCC to show me the commands? ../lib/odp-util.c:5601:9: note: expanded from macro 'SCAN_PUT' Why do academics stay as adjuncts for years rather than move around? 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. I'm using cocos2d-x-2.2.2. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? This is not a conversion at all. 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. privacy statement. While working with Threads in C, I'm facing the warning, "warning: cast to pointer from integer of different size". I'm trying to learn pthreads and thing that keeps bugging me is how do i really pass argument to the function. 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 It is purely a compile-time directive which instructs the compiler to treat expression as if it had . The main point is: a pointer has a platform dependent size. The problem was there before, you just are being notified of it. Making statements based on opinion; back them up with references or personal experience. No sense in writing a few dozen lines of extra code just to get a bunch of numbered threads. 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;. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? Can Martian regolith be easily melted with microwaves? 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. A void pointer can be really useful if the programmer is not sure about the data type of data inputted by the end user. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Setting a buffer of char* with intermediate casting to int*. Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. Again, all of the answers above missed the point badly. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Do new devs get fired if they can't solve a certain bug? Yeah, the tutorial is doing it wrong. Why does Mister Mxyzptlk need to have a weakness in the comics? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Why do small African island nations perform better than African continental nations, considering democracy and human development? From what I read about casting in the C11 standard, my feeling is, that it is arguable to emit a warning on an explicit conversion. 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. Can I tell police to wait and call a lawyer when served with a search warrant? eg. Returns a value of type new-type. } SCAN_END_SINGLE(ATTR) Since gcc compiles that you are performing arithmetic between void* and an int (1024). No idea how it amassed 27 upvotes?! 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. You think by casting it here that you are avoiding the problem! To avoid truncating your pointer, cast it to a type of identical size. I have looked around and can't seem to find any information on how to do this. ../lib/odp-util.c:5603:13: note: expanded from macro 'SCAN_PUT' 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. Identify those arcade games from a 1983 Brazilian music video. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Dinesh: could you please 1) show us those. pthread passes the argument as a void*. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. As Ferruccio said, int must be replaced with intptr_t to make the program meaningful. 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. 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. There is no "correct" way to store a 64-bit pointer in an 32-bit integer. Did i have to face to unexpected runtime issues, i guess not, i've found another discussion on this -. Why does flowing off the end of a non-void function without returning a value not produce a compiler error? The preprocesor absolutely will not perform arithmetic. An object pointer (including void*) or function pointer can be converted to an integer type using reinterpret_cast. Connect and share knowledge within a single location that is structured and easy to search. @DietrichEpp can you explain what is race condition with using. That's not a good idea if the original object (that was cast to void*) was an integer. This allows you to reinterpret the void * as an int. I usually have all automatic conversion warnings effective when developing in C, and I use explicit casting in order to suppress a specific . There's no proper way to cast this to int in general case. Well occasionally send you account related emails. However the actual code in question contains an explicit c-style cast to int. What happens if you typecast as unsigned first? Pd = Pa; Similarly, Pc may be type cast to type int and assigned the value Pa. 1. You can use any other pointer, or you can use (size_t), which is 64 bits. long guarantees a pointer size on Linux on any machine. C++ how to get the address stored in a void pointer? If not, check the pointer size on your platform, define these typedefs accordingly yourself and use them. 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. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Thanks Jonathan, I was thinking about my answer in another thread: AraK is correct, passing integers a pointers are not necessarily interchangeable. So reinterpret_cast has casted it to long type and then static_cast safely casts long to int, if you are ready do truncte the data. Here, the Java first converts the int type data into the double type. 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 It is commonly called a pointer to T and its type is T*. To learn more, see our tips on writing great answers. If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. 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). What you do here is undefined behavior, and undefined behavior of very practical sort.