Not the answer you're looking for? How can this new ban on drag possibly be considered constitutional? The int data type is the primary integer data type in SQL Server. FAILED: lib/libopenvswitch.a.p/odp-util.c.obj What is the purpose of non-series Shimano components? Why is there a voltage on my HDMI and coaxial cables? @kshegunov said in Number Type Cast: const void * x; int y = int (x); compiles just fine. Mutually exclusive execution using std::atomic? Can Martian regolith be easily melted with microwaves? 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. The following program casts a double to an int. Passing arguments to pthread_create - invalid conversion from void(*)() to void(*)(void*). The only alternative is really to take time and fix all 64-bit code issues, of which there may be some non-trivial issues. This is known as implicit type casting or type promotion, compiler automatically converts smaller data type to larger data type. Once you manage to make this cast, then what?! Mutually exclusive execution using std::atomic? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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. itch" "-I..\include\windows" "-Iinclude" "-I..\include" "-I..\datapath-windows\include" "-IC:\PTHREADS-BUILT\include" "-Xclang" "-fcolor-diagnostics" "-pipe" 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 rev2023.3.3.43278. "After the incident", I started to be more careful not to trip over things. I have a two functions, one that returns an int, and one that takes a const void* as an argument. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? How Intuit democratizes AI development across teams through reusability. If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. But assuming that it is, as long as the caller and the callee agree, you can do that sort of thing. If your standard library (even if it is not C99) happens to provide these types - use them. A long long would not work for 32bit systems and a long would not work for 64 bit Windows (while 64bit Unix and Unix-like systems like OS X use the LP64 data model, in which a long is 64bit, 64bit Windows uses the LLP64 data model, in which a long has a size of 32bit (http://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models)). ", "!"? What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? Maybe you can try this too. 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). But the problem has still happened. Is it possible to create a concave light? From that point on, you are dealing with 32 bits. Can I tell police to wait and call a lawyer when served with a search warrant? I guess the other important fact is that the cast operator has higher precedence that the multiplication operator. for saving RAM), use union, and make sure, if the mem address is treated as an int only if you know it was last set as an int. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. . Taking the above declarations of A, D, ch of the . Thanks for contributing an answer to Stack Overflow! @DavidHeffernan, sane thread APIs wouldn't send integral data to the thread procedures, they would send pointers. @BlueMoon Thanks a lot! Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. eg. Why do academics stay as adjuncts for years rather than move around? It's always a good practice to put your #define's in brackets to avoid such surprise. Yeah, the tutorial is doing it wrong. Asking for help, clarification, or responding to other answers. Casting an open pointer to other pointer types and casting other pointer types to an open pointer does not result in a compile time error. Using Kolmogorov complexity to measure difficulty of problems? Thanks Jonathan, I was thinking about my answer in another thread: AraK is correct, passing integers a pointers are not necessarily interchangeable. Again, all of the answers above missed the point badly. Example: int x=7, y=5; float z; z=x/y; /*Here the value of z is 1*/. It's an int type guaranteed to be big enough to contain a pointer. Find centralized, trusted content and collaborate around the technologies you use most. How to use Slater Type Orbitals as a basis functions in matrix method correctly? However, I believe that even if the define was for the "65536", it would not be what @kaetzacoatl wanted. 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. lexborisov Modest Public. This is an old C callback mechanism so you can't change that. Did i have to face to unexpected runtime issues, i guess not, i've found another discussion on this -. rev2023.3.3.43278. XCode 5.1 is change all architecture to 64 bit. Whats the grammar of "For those whose stories they are"? If you need to keep the returned address, just keep it as void*. In this case, casting the pointer back to an integer is meaningless, because . return ((void **) returnPtr);} /* Matrix() */. There is absolutely not gurantee that sizeof(int) <= sizeof(void*). AC Op-amp integrator with DC Gain Control in LTspice. To learn more, see our tips on writing great answers. Functions return bigint only if the parameter expression is a bigint data type. Linear regulator thermal information missing in datasheet. 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). Then i can continue compiling. 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. Making statements based on opinion; back them up with references or personal experience. Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. 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. A nit: in your version, the cast to void * is unnecessary. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The problem just occur with Xcode 5.1. A pointer converted to an integer of sufficient size and back to the same pointer type is guaranteed to have its original value, otherwise the resulting pointer cannot be dereferenced safely ( the round-trip conversion in the opposite direction is not guaranteed [.]) 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 preprocessor will replace your code by this: This is unlikely what you are trying to do. You are correct, but cocos actually only uses that address as a unique id. 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. Find centralized, trusted content and collaborate around the technologies you use most. This method will not work on 64 bit Big Endian platform, so it unnecessarily breaks portability. The calculated expression consists of two operations. If your standard library (even if it is not C99) happens to provide these types - use them. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~. 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. rev2023.3.3.43278. Find centralized, trusted content and collaborate around the technologies you use most. In the best case this will give the same results as the original code, with no advantages, but in the worst case it will fail in multiple catastrophic ways (type punning, endianness, less efficient, etc. Here, the Java first converts the int type data into the double type. Disconnect between goals and daily tasksIs it me, or the industry? Surely the solution is to change the type of ids from int to type that is sufficiently large to hold a pointer. Half your pointer will be garbage. Create an account to follow your favorite communities and start taking part in conversations. He should pass the address of the integer, the thread should get that address, Note: This is only appropriate is you cast the. You can convert the values from one type to another explicitly using the cast operator as follows (type_name) expression To learn more, see our tips on writing great answers. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Converts between types using a combination of implicit and user-defined conversions. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. how to cascade 2d int array to 2d void pointer array? We have to pass address of the variable to the function because in function definition argument is pointer variable. LLNL's tutorial is bad and they should feel bad. use $(ARCHS_STANDARD_32_BIT) at Architecture instead of $(ARCHS_STANDARD). 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. This is a fine way to pass integers to new pthreads, if that is what you need. Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, "what happen when typcating normal variable to void* or any pointer 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. 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; This is not a conversion at all. Pull requests. From the question I presume the OP does. If not, check the pointer size on your platform, define these typedefs accordingly yourself and use them. 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. If you convert (void*) to (long) no precision is lost, then by assigning the (long) to an (int), it properly truncates the number to fit. 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;. privacy statement. ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' Yeah, the tutorial is doing it wrong. Floating-point conversions In both cases, converting the pointer to an integer type that's too small to represent all pointer values is a bug. 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. @jackdoe: It's a waste of human life to write code that "you may need in the future". On most platforms pointers and longs are the same size, but ints and pointers often are not the same size on 64bit platforms. To avoid truncating your pointer, cast it to a type of identical size. What does casting to void* does when passing arguments to variadic functions? The correct answer is, if one does not mind losing data precision. Whats the grammar of "For those whose stories they are"? 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. 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. 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). 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; Recovering from a blunder I made while emailing a professor. The dynamic_cast<>operator provides a way to check the actual type of a pointer to a polymorphic class. Making statements based on opinion; back them up with references or personal experience. Based on the design of this function, which modification is right. 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. How do I work around the GCC "error: cast from SourceLocation* to int loses precision" error when compiling cmockery.c? you can just change architecture to support 32 bit compilation by all below in in Build Settings. If you preorder a special airline meal (e.g. LLNL's tutorial is bad and they should feel bad. A void pointer can be really useful if the programmer is not sure about the data type of data inputted by the end user. I need to cast the int from the first function so that I can use it as an argument for the second function. But you seem to suggest by your answer that the user can pass 5 to pthread_create and then perform the above cast to get it back. You need to pass an actual pointer. All character types are to be converted to an integer. 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). Use returnPtr[j] = (void *) ((long)ptr + i); ). For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. linux c-pthreads: problem with local variables. Making statements based on opinion; back them up with references or personal experience. 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 can use any other pointer, or you can use (size_t), which is 64 bits. How Intuit democratizes AI development across teams through reusability. 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. You may declare a const int variable and cast its reference to the void*. returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); rev2023.3.3.43278. Acidity of alcohols and basicity of amines. Most answers just try to extract 32 useless bits out of the argument. C / C++ Forums on Bytes. Thus as a result it may be less error prone to generate a pointer dynamcially and use that. How create a simple program using threads in C? Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Basically its a better version of (void *)i. SCAN_SINGLE("skb_priority(", uint32_t, u32, OVS_KEY_ATTR_PRIORITY); } SCAN_END_SINGLE(ATTR) Is a PhD visitor considered as a visiting scholar. And, most of these will not even work on gcc4. How to tell which packages are held back due to phased updates, Identify those arcade games from a 1983 Brazilian music video. Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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). Why does setupterm terminate the program? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. All float types are to be converted to double. SCAN_PUT(ATTR, NULL); If you call your thread creation function like this, then the void* arriving inside of myFcn has the value of the int you put into it. The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. */ >> -bool >> +enum conversion_safety >> unsafe_conversion_p (tree type, tree expr, bool . 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. What you do here is undefined behavior, and undefined behavior of very practical sort. Why is there a voltage on my HDMI and coaxial cables? A nit: in your version, the cast to void * is unnecessary. However the actual code in question contains an explicit c-style cast to int. If the destination type is bool, this is a boolean conversion (see below). This page was last modified on 12 February 2023, at 18:25. Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? If the source type is bool, the value false is converted to zero and the value true is converted to the value one of the destination type (note that if the destination type is int, this is an integer promotion, not an integer conversion). How can this new ban on drag possibly be considered constitutional? SCAN_PUT_ATTR(mask, ATTR, smask, FUNC); I agree passing a dynamically allocated pointer is fine (and I think the best way). Why do small African island nations perform better than African continental nations, considering democracy and human development? This will get you a pointer from a 32 bit offset: A function pointer is incompatible to void* (and any other non function pointer). Connect and share knowledge within a single location that is structured and easy to search. 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. 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. Keep in mind that thrArg should exist till the myFcn() uses it. SCAN_PUT_ATTR(key, ATTR, skey, FUNC); 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. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. Issues. byte -> short -> char -> int -> long -> float -> double. What is the point of Thrower's Bandolier? Any help with this is appreciated. This allows you to reinterpret the void * as an int. On all of them int is 32bit, not 16bit. [that could be a TODO - not to delay solving the ICE]. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. error: cast from pointer to smaller type 'unsigned int' loses information. What does it mean to convert int to void* or vice versa? Update: Today, i download the latest version of cocos2d-x (cocos2d-x 2.2.3). It is easier to understand and write than any other assembly language. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? Don't do that. No sense in writing a few dozen lines of extra code just to get a bunch of numbered threads. C99 defines the types "intptr_t" and "uintptr_t" which do . In the case of Widening Type Casting, the lower data type (having smaller size) is converted into the higher data type (having larger size). If this is the data to a thread procedure, then you quite commonly want to pass by value. If you really need such trickery, then consider one of dedicated types, which are intptr_t and uintptr_t. what happens when we typecast normal variable to void* or any pointer variable? 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. I'm using cocos2d-x-2.2.2. I wish that you write those answer first than the explanation. C++ how to get the address stored in a void pointer? It solved my problem too. Where does this (supposedly) Gibson quote come from? Disconnect between goals and daily tasksIs it me, or the industry? Sign in Star 675. If int is no larger than pointer to void then one way to store the value is by simply copying the bytes: int i . So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. How do I force make/GCC to show me the commands? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. An object pointer (including void*) or function pointer can be converted to an integer type using reinterpret_cast. long guarantees a pointer size on Linux on any machine. 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]. Please tell me error: cast from 'void*' to 'int' loses precision, How Intuit democratizes AI development across teams through reusability. Fork 63. *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 . You can also convert values from one type to another explicitly using the cast operator (see Chapter 5 ): ( type_name) expression In the following example, the cast operator causes the division of one integer variable by another to be performed as a floating-point operation: int sum = 22, count = 5; double mean = (double)sum / count; @Artelius: Which, presumably, is exactly what Joshua did: A C++ reinterpret cast will not solve the problem. 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.. You are getting warnings due to casting a void* to a type of a different size. Please unaccept the answer you have chosen as it is wrong (as the comments below it say) and will lead to bugs. 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. x is a local variable and its lifetime ends as soon as control leaves the scope it was defined in. 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 whether it was an actual problem is a different matter though. You are just making it bigger by tricking the compiler and the ABI. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. Why is there a voltage on my HDMI and coaxial cables? Casting a pointer to void* and back is valid use of reinterpret_cast<>. SCAN_PUT(ATTR, NULL); Don't do that. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. ^~~~~~~~~~~~~~~~~~~~~ Before I update Xcode, my project still can build and run normally with all devices. 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.
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