cast to void *' from smaller integer type 'intcast to void *' from smaller integer type 'int
. The result is the same as implicit conversion from the enum's underlying type to the destination type. @DietrichEpp can you explain what is race condition with using. 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. rev2023.3.3.43278. On most platforms pointers and longs are the same size, but ints and pointers often are not the same size on 64bit platforms. Using Kolmogorov complexity to measure difficulty of problems? unsigned long call_fn = (unsigned long)FUNC; ../lib/odp-util.c:5658:9: note: expanded from macro 'SCAN_END_SINGLE' All float types are to be converted to double. C/C++ , Cerror: cast to 'void *' from smaller integer type 'int'. 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:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] You use the address-of operator & to do that. As with all cast expressions, the result is: Two objects a and b are pointer-interconvertible if: static_cast may also be used to disambiguate function overloads by performing a function-to-pointer conversion to specific type, as in. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Dinesh: could you please 1) show us those. 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 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. 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 is why you got Error 1 C2036, from your post. How do I check if a string represents a number (float or int)? B programing language is a language based on basic combined programming or a BCPL, and it is the precursor of the C programming language. Thanks Jonathan, I was thinking about my answer in another thread: AraK is correct, passing integers a pointers are not necessarily interchangeable. ^~~~~~~~~~~~~~~~~~~ Casting arguments inside the function is a lot safer. In such a case the programmer can use a void pointer to point to the location of the unknown data type. You need to pass an actual pointer. Not the answer you're looking for? 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 only alternative is really to take time and fix all 64-bit code issues, of which there may be some non-trivial issues. Why does setupterm terminate the program? [] 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). Well it does this because you are converting a 64 bits pointer to an 32 bits integer so you loose information. I am compiling this program in linux gcc compiler.. As Ferruccio said, int must be replaced with intptr_t to make the program meaningful. The int data type is the primary integer data type in SQL Server. Safe downcast may be done with dynamic_cast. 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. rev2023.3.3.43278. If you really need such trickery, then consider one of dedicated types, which are intptr_t and uintptr_t. ncdu: What's going on with this second size column? 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 cannot reverse my upvote of user384706's answer, but it's wrong. In simple example code like this it's very easy to convince yourself that there's no problem, but in more elaborate real-world scenarios it's very easy to make this mistake inadvertently. The program can be set in such a way to ask the user to inform the type of data and . Only the following conversions can be done with static_cast, except when such conversions would cast away constness or volatility. To access the object value, use the * dereference operator: int * p; assert (p == null ); p = new int (5); assert (p != null ); assert (*p == 5); (*p)++; assert (*p == 6); If a pointer contains a null value, it is not pointing to a valid object. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? 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. 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. ", "!"? (void *)i Error: cast to 'void *' from smaller integer type 'int' PS: UBUNTUCLANG3.5 clang -O0 -std=gnu11 -march=native -lm -lpthread pagerank.c -o pagerank c pthreads 4 10.3k 2 21 2015-06-05 The proper way is to cast it to another pointer type. The calculated expression consists of two operations. 10) A prvalue of type pointer to void (possibly cv-qualified) can be converted to pointer to any object type. To learn more, see our tips on writing great answers. SCAN_SINGLE("skb_priority(", uint32_t, u32, OVS_KEY_ATTR_PRIORITY); For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? What happens if you typecast as unsigned first? C / C++ Forums on Bytes. property that any valid pointer to void can be converted to this type, 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 have a function with prototype void* myFcn(void* arg) which is used as the starting point for a pthread. If any, how can the original function works without errors if we just ignore the warning. The problem is not with casting, but with the target type loosing half of the pointer. When is casting void pointer needed in C? As a result of the integer division 3/2 we get the value 1, which is of the int type. There is absolutely not gurantee that sizeof(int) <= sizeof(void*). And, most of these will not even work on gcc4. 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. Again, all of the answers above missed the point badly. A missing cast in the new fast > enumeration code. 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. 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. It solved my problem too. How create a simple program using threads in C? 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; Converting one datatype into another is known as type casting or, type-conversion. 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 This explicit cast clearly tells the compiler "Shut up, I know that this code does not look correct, but I do know what I am doing". To be honest, I think, clang is too restrictive here. The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Most answers just try to extract 32 useless bits out of the argument. Anw, the project still build and run normally when i use Xcode 5.0 with iOS 7.0. equal to the original pointer: First you are using a define, which is not a variable. rev2023.3.3.43278. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Connect and share knowledge within a single location that is structured and easy to search. 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. Connect and share knowledge within a single location that is structured and easy to search. This page was last modified on 12 February 2023, at 18:25. Update: Today, i download the latest version of cocos2d-x (cocos2d-x 2.2.3). Returns a value of type new-type. How to tell which packages are held back due to phased updates, Identify those arcade games from a 1983 Brazilian music video. On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. that any valid pointer to void can be converted to this type, then This will get you a pointer from a 32 bit offset: A function pointer is incompatible to void* (and any other non function pointer). 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. You can fix this error by replacing this line of code. This is flat out wrong. To learn more, see our tips on writing great answers. Can Martian regolith be easily melted with microwaves? "-D_FILE_OFFSET_BITS=64" "-Wall" "-Winvalid-pch" "-g" "-Wthread-safety" "-Wno-microsoft-enum-forward-reference" "-Wno-unused-function" "-Wno-sometimes-unini A nit: in your version, the cast to void * is unnecessary. this way I convert an int to a void* which is much better than converting a void* to an int. Yeah, the tutorial is doing it wrong. ../lib/odp-util.c:5658:9: note: expanded from macro 'SCAN_END_SINGLE' 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. 7.1 New Cast Operations The C++ standard defines new cast operations that provide finer control than previous cast operations. Not the answer you're looking for? this way you won't get any warning. What is the point of Thrower's Bandolier? Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. Whats the grammar of "For those whose stories they are"? How do I set, clear, and toggle a single bit? Error while setting app icon and launch image in xcode 5.1. Such pointers can be stored in 32-bit data types (for instance, int, DWORD). Linear regulator thermal information missing in datasheet. How to notate a grace note at the start of a bar with lilypond? 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. For the second example you can make sure that sizeof(int) <= sizeof(void *) by using a static_assert -- this way at least you'll get a notice about it. you can just change architecture to support 32 bit compilation by all below in in Build Settings. An open (void) pointer can hold a pointer of any type. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin? The preprocessor will replace your code by this: This is unlikely what you are trying to do. SCAN_PUT_ATTR(key, ATTR, skey, FUNC); 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. How to use Slater Type Orbitals as a basis functions in matrix method correctly? LLNL's tutorial is bad and they should feel bad. p-util.c.obj "-c" ../lib/odp-util.c Whats the grammar of "For those whose stories they are"? Why do academics stay as adjuncts for years rather than move around? Any help with this is appreciated. Functions return bigint only if the parameter expression is a bigint data type. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? A void pointer can be really useful if the programmer is not sure about the data type of data inputted by the end user. It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. So make sure you understand what you are doing! what does it mean to convert int to void* or vice versa? this question. My code is all over the place now but I appreciate you all helping me on my journey to mastery! I am an entry level C programmer. Therefore, you need to change it to long long instead of long in windows for 64 bits. 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). Windows has 32 bit long only on 64 bit as well. Just edited. On many systems, an 8-bit unsigned int can be stored at any address while an unsigned 32-bit int must be aligned on an address that is a multiple of 4. Identify those arcade games from a 1983 Brazilian music video. What is the difference between const int*, const int * const, and int const *? What is the purpose of non-series Shimano components? 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). 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). How to use Slater Type Orbitals as a basis functions in matrix method correctly? I don't see how anything bad can happen . To subscribe to this RSS feed, copy and paste this URL into your RSS reader. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../lib/odp-util.c:5489:33: note: expanded from macro 'SCAN_PUT_ATTR' lexborisov Modest Public. It is done by the compiler on its own, without any external trigger from the user. Using indicator constraint with two variables. Noncompliant Code Example (memset())For historical reasons, certain C Standard functions accept an argument of type int and convert it to either unsigned char or plain char. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. What is the purpose of non-series Shimano components? @DavidHeffernan I rephrased that sentence a little. Making statements based on opinion; back them up with references or personal experience. vegan) just to try it, does this inconvenience the caterers and staff? 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. To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. SCAN_PUT_ATTR(mask, ATTR, smask, FUNC); 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. 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. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? 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. How do I align things in the following tabular environment? What does it mean to convert int to void* or vice versa? Why is this sentence from The Great Gatsby grammatical? Please help me compile Chez Scheme. Making statements based on opinion; back them up with references or personal experience. Does ZnSO4 + H2 at high pressure reverses to Zn + H2SO4? 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. 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. A cast specifies a conversion from one type to another.
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 Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? You can convert the values from one type to another explicitly using the cast operator as follows (type_name) expression The text was updated successfully, but these errors were encountered: You signed in with another tab or window. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Making statements based on opinion; back them up with references or personal experience. What I am saying is that it would be safer to use new(5) rather than 5 and deal with it appropriately at the other end. 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. */void **MatrixIB (unsigned long x, unsigned long y, int size){ void *ptr; void **returnPtr; register unsigned long i, j; returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); for (i=0, j=0; j