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. C / C++ Forums on Bytes. Linear regulator thermal information missing in datasheet. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, "what happen when typcating normal variable to void* or any pointer variable?" Functions return bigint only if the parameter expression is a bigint data type. Don't do that. "-I.." "-Iinclude\openflow" "-I..\include\openflow" "-Iinclude\openvswitch" "-I..\include\openvsw It's always a good practice to put your #define's in brackets to avoid such surprise. 471,961 Members | 900 Online. 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 value of float variable is= 37.75. 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;. 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. B programing language is a language based on basic combined programming or a BCPL, and it is the precursor of the C programming language. The problem is not with casting, but with the target type loosing half of the pointer. reinterpret_cast is a type of casting operator used in C++. 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. I would create a structure and pass that as void* to pthread_create. @Martin York: No, it doesn't depend on endiannness. ^~~~~~~~~~~~~~~~~~~~ If this is the data to a thread procedure, then you quite commonly want to pass by value. An object pointer (including void*) or function pointer can be converted to an integer type using reinterpret_cast. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Why is there a voltage on my HDMI and coaxial cables? ../lib/odp-util.c:5658:9: note: expanded from macro 'SCAN_END_SINGLE' I have a two functions, one that returns an int, and one that takes a const void* as an argument. How to correctly cast a pointer to int in a 64-bit application? Pd = Pa; Similarly, Pc may be type cast to type int and assigned the value Pa. 1. If you cast an int pointer int, you might get back a different integer. It is done by the compiler on its own, without any external trigger from the user. Already on GitHub? How can this new ban on drag possibly be considered constitutional? to the original pointer: The following type designates an unsigned integer type with the The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. @DavidHeffernan, sane thread APIs wouldn't send integral data to the thread procedures, they would send pointers. 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. Use #include to define it. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? @Xax: Here's a fixed version, without the race condition: gist.github.com/depp/241d6f839b799042c409, gist.github.com/depp/3f04508a88a114734195, How Intuit democratizes AI development across teams through reusability. 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. Is it possible to create a concave light? Can I tell police to wait and call a lawyer when served with a search warrant? You can use a 64 bits integer instead howerver I usually use a function with the right prototype and I cast the function type : You could use this code, and it would do the same thing as casting ptr to (char*). Note:You might receive a runtime exception if the pointer contains a value unsuitable for the context. ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] Converting a pointer to an integer whose result cannot represented in the integer type is undefined behavior is C and prohibited in C++. : iPhone Retina 4-inch 64-bit) is selected. 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. What is the point of Thrower's Bandolier? vegan) just to try it, does this inconvenience the caterers and staff? I'm new to coding and am trying to implement a simple program on my own, that prompts the user the number of residents in an apt complex, the prompts the user to enter the names and apt numbers of each resident. Maybe you can try this too. Asking for help, clarification, or responding to other answers. However the actual code in question contains an explicit c-style cast to int. And you can't pass a pointer to a stack based object from the other thread as it may no longer be valid. (i.e. Implicit Type Conversion is also known as 'automatic type conversion'. with ids being an array of ints and touch being a pointer. -1, Uggh. [] 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). When is casting void pointer needed in C? While working with Threads in C, I'm facing the warning, "warning: cast to pointer from integer of different size". This will only compile if the destination type is long enough. Asking for help, clarification, or responding to other answers. 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. what does it mean to convert int to void* or vice versa? Taking the above declarations of A, D, ch of the . Implementing From will result in the Into implementation but not vice-versa. Yeah, the tutorial is doing it wrong. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. For example, if youwrite ((int*)ptr + 1), it will add 4 bytes to the pointer, because "ints" are 4 bytes each. How do I align things in the following tabular environment? You are getting warnings due to casting a void* to a type of a different size. This will get you a pointer from a 32 bit offset: A function pointer is incompatible to void* (and any other non function pointer). 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. Issues. SCAN_PUT(ATTR, NULL); Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Thanks for contributing an answer to Stack Overflow! Not the answer you're looking for? 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. Usually that means the pointer is allocated with. You need to pass an actual pointer. Have a question about this project? Making statements based on opinion; back them up with references or personal experience. But the problem has still happened. 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. itch" "-I..\include\windows" "-Iinclude" "-I..\include" "-I..\datapath-windows\include" "-IC:\PTHREADS-BUILT\include" "-Xclang" "-fcolor-diagnostics" "-pipe" Fork 63. 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). What does casting to void* does when passing arguments to variadic functions? Mutually exclusive execution using std::atomic? 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. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? What does it mean to convert int to void* or vice versa? This is a fine way to pass integers to new pthreads, if that is what you need. If the destination type is bool, this is a boolean conversion (see below). Please help me compile Chez Scheme. 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. For example, if you want to store a 'long' value into a simple integer then you can type cast 'long' to 'int'. Update: Today, i download the latest version of cocos2d-x (cocos2d-x 2.2.3). Bulk update symbol size units from mm to map units in rule-based symbology. *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 . So make sure you understand what you are doing! What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. @kshegunov said in Number Type Cast: const void * x; int y = int (x); compiles just fine. For example, the main thread could wait for all of the other threads to end before terminating. Just edited. I understood, but that would introduce dynamic memory and ugly lifetime issues (an object allocated by one thread must be freed by some other) - all just to pass an. 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. If not, check the pointer size on your platform, define these typedefs accordingly yourself and use them. Note the difference between the type casting of a variable and type casting of a pointer. Bulk update symbol size units from mm to map units in rule-based symbology. Therefore it is perfectly valid for the compiler to throw an error for a line like. 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Here is my code: I already tried (void*)M_TABLE_SIZE but then I get an error that I cannot use the * operator. Here, the Java first converts the int type data into the double type. Thus as a result it may be less error prone to generate a pointer dynamcially and use that. I am an entry level C programmer. Does Counterspell prevent from any further spells being cast on a given turn? 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; It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. rev2023.3.3.43278. Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul 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. 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. From that point on, you are dealing with 32 bits. Do new devs get fired if they can't solve a certain bug? However even though their types are different, the address is going to be the same. There is no "correct" way to store a 64-bit pointer in an 32-bit integer. SCAN_PUT_ATTR(mask, ATTR, smask, FUNC); 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. ../lib/odp-util.c:5601:9: note: expanded from macro 'SCAN_PUT' Use returnPtr[j] = (void *) ((long)ptr + i); ). 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. Error while setting app icon and launch image in xcode 5.1. The correct answer is, if one does not mind losing data precision. Projects. Why does setupterm terminate the program? How to make compiler not show int to void pointer cast warnings, incompatible pointer types assigning to 'void (*)(void *)' from 'int (int *)'. rev2023.3.3.43278. To learn more, see our tips on writing great answers. ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] 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. */ >> -bool >> +enum conversion_safety >> unsafe_conversion_p (tree type, tree expr, bool . Making statements based on opinion; back them up with references or personal experience. 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 Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. So,solution #3 works just fine. This is flat out wrong. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. I think the solution 3> should be the correct one. Type casting is when you assign a value of one primitive data type to another type. 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. From the question I presume the OP does. I cannot reverse my upvote of user384706's answer, but it's wrong. To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. Why is there a voltage on my HDMI and coaxial cables? (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. There is absolutely not gurantee that sizeof(int) <= sizeof(void*). 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 In such condition type conversion (type promotion) takes place to avoid loss of data. Windows has 32 bit long only on 64 bit as well. I am compiling this program in linux gcc compiler.. ncdu: What's going on with this second size column? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. However, I believe that even if the define was for the "65536", it would not be what @kaetzacoatl wanted. Thanks for contributing an answer to Stack Overflow! 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. this way you won't get any warning. 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. Since all pointers on 64-bit Windows are 64 bits, you are growing the data size from 32 bits backto 64 bits. 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]. If the sizes are different then endianess comes into play. FAILED: lib/libopenvswitch.a.p/odp-util.c.obj Does melting sea ices rises global sea level? (int) pthread_self() 64int48intuintptr_t (unsigned int) B language was designed to develop . I'm unfamiliar with XCode, but the solution should be something like follows: Most of the "solutions" above can lose part of the pointer address when casting to a smaller type. The result is the same as implicit conversion from the enum's underlying type to the destination type. If you need to keep the returned address, just keep it as void*. Basically its a better version of (void *)i. But this code pass the normal variable .. Or, they are all wrong. Well occasionally send you account related emails. 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" (. 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. I guess the other important fact is that the cast operator has higher precedence that the multiplication operator. If your standard library (even if it is not C99) happens to provide these types - use them. You should perform type conversion based on 64bit build system because the type "int" supports only -32768 ~ 32768. The problem was there before, you just are being notified of it. windows meson: cast to smaller integer type 'unsigned long' from 'void *'. Click to see the query in the CodeQL repository. Mutually exclusive execution using std::atomic? Since gcc compiles that you are performing arithmetic between void* and an int (1024). This page was last modified on 12 February 2023, at 18:25. Disconnect between goals and daily tasksIs it me, or the industry? You are just making it bigger by tricking the compiler and the ABI. In Java, there are two types of casting: Widening Casting (automatically) - converting a smaller type to a larger type size. 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. Using Kolmogorov complexity to measure difficulty of problems? 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.. . ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' This is what the second warning is telling you. what happens when we typecast normal variable to void* or any pointer variable? If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? 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 method will not work on 64 bit Big Endian platform, so it unnecessarily breaks portability. Wrong. 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 To subscribe to this RSS feed, copy and paste this URL into your RSS reader. The problem just occur with Xcode 5.1. How to use Slater Type Orbitals as a basis functions in matrix method correctly? I'm trying to learn pthreads and thing that keeps bugging me is how do i really pass argument to the function. void* -> integer -> void* rather than integer -> void* -> integer. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. } SCAN_END_SINGLE(ATTR) No idea how it amassed 27 upvotes?! SCAN_PUT_ATTR(key, ATTR, skey, FUNC); Did i have to face to unexpected runtime issues, i guess not, i've found another discussion on this -. An open (void) pointer can hold a pointer of any type. Why does flowing off the end of a non-void function without returning a value not produce a compiler error? Mutually exclusive execution using std::atomic? You can convert the values from one type to another explicitly using the cast operator as follows (type_name) expression Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Why does Mister Mxyzptlk need to have a weakness in the comics? for (i=0, j=0; j

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