cast to void *' from smaller integer type 'int

The difference between the phonemes /p/ and /b/ in Japanese. And then assign it to the double variable. Whats the grammar of "For those whose stories they are"? Netdev Archive on lore.kernel.org help / color / mirror / Atom feed * [mst-vhost:vhost 5/52] drivers/block/virtio_blk.c:539:21: warning: assignment to 'void *' from . property that any valid pointer to void can be converted to this type, Whats the grammar of "For those whose stories they are"? ^~~~~~~~~~~~~~~~~~~~~ The subreddit for the C programming language, Press J to jump to the feed. unsigned long call_fn = (unsigned long)FUNC; You cannot just cast the 32-bit variable to a pointer, because that pointer on a 64-bit machine is twice as long. 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. It's an int type guaranteed to be big enough to contain a pointer. 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. Replacing broken pins/legs on a DIP IC package, How to handle a hobby that makes income in US. To cast such pointers to 32-bit types and vice versa special functions are used: void * Handle64ToHandle ( const void * POINTER_64 h ) void * POINTER_64 HandleToHandle64 ( const void *h ) long HandleToLong ( const void *h ) unsigned long HandleToUlong ( const void *h ) this way I convert an int to a void* which is much better than converting a void* to an int. If the function had the correct signature you would not need to cast it explicitly. A sane compiler may throw a warning on lines like this but by no way it should throw an error, because this code is NOT wrong, it is just potentially error-prone, but can be perfectly valid. Are there tables of wastage rates for different fruit and veg? But then you need to cast your arguments inside your thread function which is quite unsafe cf. SCAN_PUT(ATTR, NULL); Surely the solution is to change the type of ids from int to type that is sufficiently large to hold a pointer. rev2023.3.3.43278. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? Is it possible to create a concave light? 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. No sense in writing a few dozen lines of extra code just to get a bunch of numbered threads. casting from int to void* and back to int. To avoid truncating your pointer, cast it to a type of identical size. *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 . Or, they are all wrong. This example is noncompliant on an implementation where pointers are 64 bits and unsigned integers are 32 bits because the result of converting the 64-bit ptr cannot be represented in the 32-bit integer type. even though the compiler doesn't know you only ever pass myFcn to pthread_create in conjunction with an integer. To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' 1. What is the point of Thrower's Bandolier? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. To learn more, see our tips on writing great answers. B programing language is a language based on basic combined programming or a BCPL, and it is the precursor of the C programming language. But the problem has still happened. SCAN_SINGLE("skb_priority(", uint32_t, u32, OVS_KEY_ATTR_PRIORITY); privacy statement. 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. I am compiling this program in linux gcc compiler.. 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. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [that could be a TODO - not to delay solving the ICE]. How to make compiler not show int to void pointer cast warnings, incompatible pointer types assigning to 'void (*)(void *)' from 'int (int *)'. Using indicator constraint with two variables. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? 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. But, sure, in that specific case you can pass a local variable address, type casting integer to void* [duplicate]. Connect and share knowledge within a single location that is structured and easy to search. You are getting warnings due to casting a void* to a type of a different size. Asking for help, clarification, or responding to other answers. 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 Connect and share knowledge within a single location that is structured and easy to search. Converting a pointer to an integer whose result cannot represented in the integer type is undefined behavior is C and prohibited in C++. Bulk update symbol size units from mm to map units in rule-based symbology. (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 If the original pointer value represents an address of a byte in memory that does not satisfy the alignment requirement of the target type, then the resulting pointer value is unspecified. rev2023.3.3.43278. Getting Command /bin/sh failed with exit code 65 Error with Xcode 5.1 . a is of type int[4], which can be implicitly cast to int* (ie, a pointer to an int) &a is of type int(*)[4] (ie: a pointer to an array of 4 ints). How do I force make/GCC to show me the commands? */ >> -bool >> +enum conversion_safety >> unsafe_conversion_p (tree type, tree expr, bool . By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The 32 remaining bits stored inside int are insufficient to reconstruct a pointer to the thread function. I'm trying to create a void* from an int. For a fairly recent compiler (that supports C99) you should not store or represent address as plain int value. Making statements based on opinion; back them up with references or personal experience. If this is the data to a thread procedure, then you quite commonly want to pass by value. 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! Casting a pointer to void* and back is valid use of reinterpret_cast<>. If the sizes are different then endianess comes into play. ", "!"? The text was updated successfully, but these errors were encountered: You signed in with another tab or window. Here is my code: I already tried (void*)M_TABLE_SIZE but then I get an error that I cannot use the * operator. On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. This answer is incorrect for the reasons that have already been mentioned in the comment of, Error "Cast from pointer to smaller type 'int' loses information" in EAGLView.mm when update Xcode to 5.1 (5B130a), http://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models, http://stackoverflow.com/questions/18913906/xcode-5-and-ios-7-architecture-and-valid-architectures, How Intuit democratizes AI development across teams through reusability. Then i can continue compiling. Thanks for contributing an answer to Stack Overflow! Instead of using a long cast, you should cast to size_t. For example, the main thread could wait for all of the other threads to end before terminating. If pointers are 64 bits and ints are 32 bits, an int is too small to hold a pointer value. Use #include to define it. Why is there a voltage on my HDMI and coaxial cables? 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. 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. rev2023.3.3.43278. The value of float variable is= 37.75. ../lib/odp-util.c:5603:13: note: expanded from macro 'SCAN_PUT' Find centralized, trusted content and collaborate around the technologies you use most. I wish that you write those answer first than the explanation. As was pointed out by Martin, this presumes that sizeof(void*)>=sizeof(int). Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. 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. Sign in Converting one datatype into another is known as type casting or, type-conversion. You can use any other pointer, or you can use (size_t), which is 64 bits. Terrible solution. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Such pointers can be stored in 32-bit data types (for instance, int, DWORD). @BlueMoon Thanks a lot! Functions return bigint only if the parameter expression is a bigint data type. If you preorder a special airline meal (e.g. Can I tell police to wait and call a lawyer when served with a search warrant? Using Kolmogorov complexity to measure difficulty of problems? 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. What I am trying to emphasis that conversion from int to pointer and back again can be frough with problems as you move from platform to platform. He should pass the address of the integer, the thread should get that address, Note: This is only appropriate is you cast the. returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); Half your pointer will be garbage. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, error: cast from void* to int loses precision, cast to pointer from integer of different size, pthread code. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Dinesh: could you please 1) show us those. 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 To learn more, see our tips on writing great answers. If you cast an int pointer int, you might get back a different integer. The proper way is to cast it to another pointer type. 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; 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. Recovering from a blunder I made while emailing a professor. C / C++ Forums on Bytes. 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. But I don't want to edit code in "EAGLView.mm" because it's a "library file". 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; It is purely a compile-time directive which instructs the compiler to treat expression as if it had . 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. ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin? error: comparison between pointer and integer ('int' and 'string' (aka 'char *')), CS50 Caesar program is working but check50 says it isn't. The dynamic_cast<>operator provides a way to check the actual type of a pointer to a polymorphic class. Therefore, you need to change it to long long instead of long in windows for 64 bits. Just edited. use $(ARCHS_STANDARD_32_BIT) at Architecture instead of $(ARCHS_STANDARD). 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. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? While working with Threads in C, I'm facing the warning, "warning: cast to pointer from integer of different size". p-util.c.obj "-c" ../lib/odp-util.c vegan) just to try it, does this inconvenience the caterers and staff? The preprocessor will replace your code by this: This is unlikely what you are trying to do. SCAN_PUT_ATTR(mask, ATTR, smask, FUNC); "clang" "-Ilib\libopenvswitch.a.p" "-Ilib" "-I..\lib" "-I." This is why you got Error 1 C2036, from your post. 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). How create a simple program using threads in C? (int) pthread_self() 64int48intuintptr_t (unsigned int) 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. If int is no larger than pointer to void then one way to store the value is by simply copying the bytes: int i . error: cast from pointer to smaller type 'unsigned int' loses information. Usually that means the pointer is allocated with. Connect and share knowledge within a single location that is structured and easy to search. For example, if youwrite ((int*)ptr + 1), it will add 4 bytes to the pointer, because "ints" are 4 bytes each. @DietrichEpp can you explain what is race condition with using. 10) A prvalue of type pointer to void (possibly cv-qualified) can be converted to pointer to any object type. @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. The difference between a and &a is the type. Linear regulator thermal information missing in datasheet. How to notate a grace note at the start of a bar with lilypond? /** Dynamically allocate a 2d (x*y) array of elements of size _size_ bytes. It is easier to understand and write than any other assembly language. On all of them int is 32bit, not 16bit. x is a local variable and its lifetime ends as soon as control leaves the scope it was defined in. How to use Slater Type Orbitals as a basis functions in matrix method correctly? Why do small African island nations perform better than African continental nations, considering democracy and human development? The most general answer is - in no way. Why do academics stay as adjuncts for years rather than move around? It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. And when assigning to a void pointer, all type information is lost. Yeah, the tutorial is doing it wrong. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? 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]. Using Kolmogorov complexity to measure difficulty of problems? This is a fine way to pass integers to new pthreads, if that is what you need. STR34-C. 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 A cast converts an object or value from one type to another. So you know you can cast it back like this. Don't do that. What you do here is undefined behavior, and undefined behavior of very practical sort. Does Counterspell prevent from any further spells being cast on a given turn? Issues. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. LLNL's tutorial is bad and they should feel bad. In such a case the programmer can use a void pointer to point to the location of the unknown data type. ", "? I would create a structure and pass that as void* to pthread_create. This is not a conversion at all. A missing cast in the new fast > enumeration code. Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. If your code has the chance to ever be ported to some platform where this doesn't hold, this won't work. linux c-pthreads: problem with local variables. 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). From the question I presume the OP does. eg. B language was designed to develop . You may declare a const int variable and cast its reference to the void*. ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] Since gcc compiles that you are performing arithmetic between void* and an int (1024). By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, "what happen when typcating normal variable to void* or any pointer variable?" rev2023.3.3.43278. Java Type Casting. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Asking for help, clarification, or responding to other answers. vegan) just to try it, does this inconvenience the caterers and staff? It is commonly called a pointer to T and its type is T*. You can fix this error by replacing this line of code. It solved my problem too. long guarantees a pointer size on Linux on any machine. Is pthread_join a must when using pthread in linux? Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? 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 reinterpret_cast is a type of casting operator used in C++. And, most of these will not even work on gcc4. For integer casts in specific, using into() signals that . Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Update: Today, i download the latest version of cocos2d-x (cocos2d-x 2.2.3). ../lib/odp-util.c:5658:9: note: expanded from macro 'SCAN_END_SINGLE' *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 .

cast to void *' from smaller integer type 'int 2023