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

rev2023.3.3.43278. 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]. But I'm nitpicking .. Find centralized, trusted content and collaborate around the technologies you use most. "-I.." "-Iinclude\openflow" "-I..\include\openflow" "-Iinclude\openvswitch" "-I..\include\openvsw To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How do I set, clear, and toggle a single bit? What is the point of Thrower's Bandolier? The program can be set in such a way to ask the user to inform the type of data and . 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. 7.1 New Cast Operations The C++ standard defines new cast operations that provide finer control than previous cast operations. The problem was there before, you just are being notified of it. Just edited. Why is this sentence from The Great Gatsby grammatical? No idea how it amassed 27 upvotes?! What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? You should perform type conversion based on 64bit build system because the type "int" supports only -32768 ~ 32768. Why does Mister Mxyzptlk need to have a weakness in the comics? windows meson: cast to smaller integer type 'unsigned long' from 'void *'. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? GitHub. If the function had the correct signature you would not need to cast it explicitly. As was pointed out by Martin, this presumes that sizeof(void*)>=sizeof(int). To subscribe to this RSS feed, copy and paste this URL into your RSS reader. } SCAN_END_SINGLE(ATTR) 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.. If the value in a pointer is cast to a different type and it does not have the correct alignment for the new type, the behavior is undefined. The dynamic_cast<>operator provides a way to check the actual type of a pointer to a polymorphic class. Find centralized, trusted content and collaborate around the technologies you use most. with ids being an array of ints and touch being a pointer. 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. Therefore it is perfectly valid for the compiler to throw an error for a line like. 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. Such pointers can be stored in 32-bit data types (for instance, int, DWORD). In such condition type conversion (type promotion) takes place to avoid loss of data. In the case of Widening Type Casting, the lower data type (having smaller size) is converted into the higher data type (having larger size). For a fairly recent compiler (that supports C99) you should not store or represent address as plain int value. Are there tables of wastage rates for different fruit and veg? 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;. this way you won't get any warning. And you can't pass a pointer to a stack based object from the other thread as it may no longer be valid. 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. In such a case the programmer can use a void pointer to point to the location of the unknown data type. Since all pointers on 64-bit Windows are 64 bits, you are growing the data size from 32 bits backto 64 bits. Press question mark to learn the rest of the keyboard shortcuts. Error while setting app icon and launch image in xcode 5.1. I am compiling this program in linux gcc compiler.. The point is (probably) that the value passed to the thread is an integer value, not really a 'void *'. You are getting warnings due to casting a void* to a type of a different size. You can only do this if you use a synchronization primitive to ensure that there is no race condition. What happens if you typecast as unsigned first? The following program casts a double to an int. Why does flowing off the end of a non-void function without returning a value not produce a compiler error? @Shahbaz you could but I will not suggest to a C newbie to use globals. Please help me compile Chez Scheme. This forum has migrated to Microsoft Q&A. This is what the second warning is telling you. Connect and share knowledge within a single location that is structured and easy to search. This is memory reinterpretation - a completely unacceptable way to do what the OP is trying to do. Find centralized, trusted content and collaborate around the technologies you use most. The subreddit for the C programming language, Press J to jump to the feed. whether it was an actual problem is a different matter though. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. Bulk update symbol size units from mm to map units in rule-based symbology. If you are going to pass the address you typically need to exert some more control over the lifetime of the object. How to convert a factor to integer\numeric without loss of information? The 32 remaining bits stored inside int are insufficient to reconstruct a pointer to the thread function. If int is no larger than pointer to void then one way to store the value is by simply copying the bytes: int i . static_cast on the other hand should deny your stripping away the const qualifier. LLNL's tutorial is bad and they should feel bad. 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. The preprocessor will replace your code by this: This is unlikely what you are trying to do. I'm trying to create a void* from an int. Losing bytes like thisis called 'truncation', and that's what the first warning is telling you. Implicit Type Conversion is also known as 'automatic type conversion'. The only alternative is really to take time and fix all 64-bit code issues, of which there may be some non-trivial issues. 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. Mutually exclusive execution using std::atomic? Don't do that. Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. Keep in mind that thrArg should exist till the myFcn() uses it. STR34-C. 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. This method will not work on 64 bit Big Endian platform, so it unnecessarily breaks portability. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. The int data type is the primary integer data type in SQL Server. The result is the same as implicit conversion from the enum's underlying type to the destination type. ), For those who are interested. property that any valid pointer to void can be converted to this type, If not, check the pointer size on your platform, define these typedefs accordingly yourself and use them. While working with Threads in C, I'm facing the warning, "warning: cast to pointer from integer of different size". 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. 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. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. Mutually exclusive execution using std::atomic? But gcc always give me a warning, that i cannot cast an int to a void*. Is it possible to create a concave light? . Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Getting Command /bin/sh failed with exit code 65 Error with Xcode 5.1 . Converting a void* to an int is non-portable way that may work or may not! 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. Can I tell police to wait and call a lawyer when served with a search warrant? And then assign it to the double variable. Asking for help, clarification, or responding to other answers. Is it possible to create a concave light? Does ZnSO4 + H2 at high pressure reverses to Zn + H2SO4? ../lib/odp-util.c:5601:9: note: expanded from macro 'SCAN_PUT' You need to pass an actual pointer. A cast converts an object or value from one type to another. In C (int)b is called an explicit conversion, i.e. 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 . I cannot reverse my upvote of user384706's answer, but it's wrong. ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' ERROR: incompatible integer to pointer conversion assigning to 'string' (aka 'char *') from 'int', error: cast to 'string' (aka 'char *') from smaller integer type 'int' [-Werror,-Wint-to-pointer-cast], error: incompatible integer to pointer conversion assigning to 'string' (aka 'char *') from 'int' C, warning: initialization of 'unsigned char' from 'uint8_t *' {aka 'unsigned char *'} makes integer from pointer without a cast [-Wint-conversion], Minimising the environmental effects of my dyson brain. If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. "I think what you should do is actually pass the address of the variable to the function" Not necessarily. On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. 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). 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 ) Surely the solution is to change the type of ids from int to type that is sufficiently large to hold a pointer. The text was updated successfully, but these errors were encountered: 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. what happens when we typecast normal variable to void* or any pointer variable? Functions return bigint only if the parameter expression is a bigint data type. ^~~~~~~~~~~~~~~~~~~~~ *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 . ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] 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; So make sure you understand what you are doing! Does Counterspell prevent from any further spells being cast on a given turn? Making statements based on opinion; back them up with references or personal experience. [that could be a TODO - not to delay solving the ICE]. 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). The reinterpret_cast makes the int the size of a pointer and the warning will stop. 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. 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. Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. @DavidHeffernan, sane thread APIs wouldn't send integral data to the thread procedures, they would send pointers. What you do here is undefined behavior, and undefined behavior of very practical sort. 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). By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. ../lib/odp-util.c:5489:33: note: expanded from macro 'SCAN_PUT_ATTR' Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? The compiler issues the "cast from integer to pointer of different size" warning whenever the value of an integer is converted to a pointer, especially when the memory allocated to a pointer is smaller than the memory allocated to an integer data type. Disconnect between goals and daily tasksIs it me, or the industry? rev2023.3.3.43278. 1. long guarantees a pointer size on Linux on any machine. Using Kolmogorov complexity to measure difficulty of problems? 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. If the sizes are different then endianess comes into play. Now, what happens when I run it with the thread sanitizer? The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. privacy statement. But, sure, in that specific case you can pass a local variable address, type casting integer to void* [duplicate].