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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. The code ((void*)ptr + 1) does not work, because the compiler has no idea what size "void" is, and therefore doesn't know how many bytes to add. 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.. Can Martian regolith be easily melted with microwaves? There's no proper way to cast this to int in general case. @jackdoe: It's a waste of human life to write code that "you may need in the future". Already on GitHub? This is why you got Error 1 C2036, from your post. @DavidHeffernan I rephrased that sentence a little. Since gcc compiles that you are performing arithmetic between void* and an int (1024). Casting Pointers - IBM This forum has migrated to Microsoft Q&A. 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; Making statements based on opinion; back them up with references or personal experience. An open (void) pointer can hold a pointer of any type. For a fairly recent compiler (that supports C99) you should not store or represent address as plain int value. Offline ImPer Westermark over 11 years ago in reply to Andy Neil Except that you sometimes stores an integer in the pointer itself. Compile error on Android ARM Issue #163 cisco/ChezScheme 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. A nit: in your version, the cast to void * is unnecessary. 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; cast operators [edit] When an expression is used in the context where a value of a different type is expected, conversionmay occur: intn =1L;// expression 1L has type long, int is expectedn =2.1;// expression 2.1 has type double, int is expectedchar*p =malloc(10);// expression malloc(10) has type void*, char* is expected The preprocessor will replace your code by this: This is unlikely what you are trying to do. error: comparison between pointer and integer ('int' and 'string' (aka 'char *')), CS50 Caesar program is working but check50 says it isn't. The int data type is the primary integer data type in SQL Server. So you know you can cast it back like this. rev2023.3.3.43278. 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. I have a function with prototype void* myFcn(void* arg) which is used as the starting point for a pthread. privacy statement. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? [Solved] Error "Cast from pointer to smaller type 'int' | 9to5Answer "I think what you should do is actually pass the address of the variable to the function" Not necessarily. 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. For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? It solved my problem too. equal to the original pointer: First you are using a define, which is not a variable. But this code pass the normal variable .. There is absolutely not gurantee that sizeof(int) <= sizeof(void*). Does a summoned creature play immediately after being summoned by a ready action? If the value is ever used as pointer again that will prove to be an extremely bad idea. @Artelius: Which, presumably, is exactly what Joshua did: A C++ reinterpret cast will not solve the problem. If the sizes are different then endianess comes into play. I cannot reverse my upvote of user384706's answer, but it's wrong. The calculated expression consists of two operations. 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 this is the data to a thread procedure, then you quite commonly want to pass by value. Here is my code: I already tried (void*)M_TABLE_SIZE but then I get an error that I cannot use the * operator. Returns a value of type new-type. 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). 7.1 New Cast Operations The C++ standard defines new cast operations that provide finer control than previous cast operations. windows meson: cast to smaller integer type 'unsigned long' from 'void *'. static_cast conversion - cppreference.com How do I force make/GCC to show me the commands? Can Martian regolith be easily melted with microwaves? 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. The correct answer is, if one does not mind losing data precision. STR34-C. Cast characters to unsigned char before converting to larger If you are planning to use pthreads and you are planning to pass the pass function to pthread_create, you have to malloc/free the arguments you are planning to use (even if the threaded function just need a single int). What you do here is undefined behavior, and undefined behavior of very practical sort. 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. See also this documentation.. From and Into are generally intended to be lossless, infalliable conversions.as on the other hand can discard data and lead to bugs in some situations, for example casting a u64 to a usize may truncate the value on a 32-bit host. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Find centralized, trusted content and collaborate around the technologies you use most. There's no proper way to cast this to int in general case. rev2023.3.3.43278. C / C++ Forums on Bytes. Here is some piece of code where that error occur: /cocos2d-x-2.2.2/cocos2dx/platform/ios/EAGLView.mm:408:18: Cast from pointer to smaller type 'int' loses information. How can this new ban on drag possibly be considered constitutional? 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. Properly casting a `void*` to an integer in C++ 24,193 Solution 1 I think using intptr_t is the correct intermediate here, since it's guaranteed to be large enough to contain the integral value of the void*, and once I have an integer value I can then truncate it without causing the compiler to complain. On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. If int is no larger than pointer to void then one way to store the value is by simply copying the bytes: int i . 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. You need to pass an actual pointer. Clang warnings for an invalid casting? - The FreeBSD Forums 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: I am using size_t here, because it is always having the same size as a pointer, no matter the platform. If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. Please help me compile Chez Scheme. : iPhone Retina 4-inch 64-bit) is selected. 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 ) 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. 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;. You can use a 64 bits integer instead howerver I usually use a function with the right prototype and I cast the function type : ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A cast is a way of explicitly informing the compiler that you intend to make the conversion and that you are aware that data loss might occur, or the cast may fail at run time. eg. Such pointers can be stored in 32-bit data types (for instance, int, DWORD). use $(ARCHS_STANDARD_32_BIT) at Architecture instead of $(ARCHS_STANDARD). If you really need such trickery, then consider one of dedicated types, which are intptr_t and uintptr_t. It generally takes place when in an expression more than one data type is present. Whats the grammar of "For those whose stories they are"? You are getting warnings due to casting a void* to a type of a different size. Converts between types using a combination of implicit and user-defined conversions. Java Type Casting. 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. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. I have looked around and can't seem to find any information on how to do this. "because the type "int" supports only -32768 ~ 32768" This is not true for any modern desktop or mobile OS or any OS that is targeted by cocos2d-x. And you can't pass a pointer to a stack based object from the other thread as it may no longer be valid. It's always a good practice to put your #define's in brackets to avoid such surprise. However even though their types are different, the address is going to be the same. [PATCH] platform/x86: hp-wmi: Fix cast to smaller integer type warning If your standard library (even if it is not C99) happens to provide these types - use them. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. sound/soc/codecs/tlv320aic32x4.c:1202:18: warning: cast to smaller 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. 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 Or, they are all wrong. 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. The problem just occur with Xcode 5.1. ncdu: What's going on with this second size column? To learn more, see our tips on writing great answers. p-util.c.obj "-c" ../lib/odp-util.c The preprocesor absolutely will not perform arithmetic. windows meson: cast to smaller integer type 'unsigned long' from 'void You could use this code, and it would do the same thing as casting ptr to (char*). Why does setupterm terminate the program? How do I work around the GCC "error: cast from SourceLocation* to int loses precision" error when compiling cmockery.c? When is casting void pointer needed in C? 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. } SCAN_END_SINGLE(ATTR) 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. clang warnings in v1.42 Issue #265 ocornut/imgui GitHub Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. I'm trying to create a void* from an int. 471,961 Members | 900 Online. Projects. For example, the main thread could wait for all of the other threads to end before terminating. Is a PhD visitor considered as a visiting scholar. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? The high-order 9 bits of the number are used to hold a flag value, and the result is converted back into a pointer. Why is this sentence from The Great Gatsby grammatical? In Java, there are two types of casting: Widening Casting (automatically) - converting a smaller type to a larger type size. should we also have a diagnostic for the (presumed) user error? Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin?). If you preorder a special airline meal (e.g. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. */ >> -bool >> +enum conversion_safety >> unsafe_conversion_p (tree type, tree expr, bool . Implicit Type Conversion is also known as 'automatic type conversion'. */void **MatrixIB (unsigned long x, unsigned long y, int size){ void *ptr; void **returnPtr; register unsigned long i, j; Again, all of the answers above missed the point badly. Thanks Jonathan, I was thinking about my answer in another thread: AraK is correct, passing integers a pointers are not necessarily interchangeable. rev2023.3.3.43278. How to use Slater Type Orbitals as a basis functions in matrix method correctly? Not the answer you're looking for? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How to correctly cast a pointer to int in a 64-bit application? ), For those who are interested. I'm using cocos2d-x-2.2.2. Put your define inside a bracket: without a problem. [that could be a TODO - not to delay solving the ICE]. However the actual code in question contains an explicit c-style cast to int. Can I tell police to wait and call a lawyer when served with a search warrant? Does melting sea ices rises global sea level? itch" "-I..\include\windows" "-Iinclude" "-I..\include" "-I..\datapath-windows\include" "-IC:\PTHREADS-BUILT\include" "-Xclang" "-fcolor-diagnostics" "-pipe" Why does flowing off the end of a non-void function without returning a value not produce a compiler error? Star 675. Use of Void pointers in C programming language Therefore, you need to change it to long long instead of long in windows for 64 bits. Usually that means the pointer is allocated with. However, I believe that even if the define was for the "65536", it would not be what @kaetzacoatl wanted. And when assigning to a void pointer, all type information is lost. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? We have to pass address of the variable to the function because in function definition argument is pointer variable. - the incident has nothing to do with me; can I use this this way? On most platforms pointers and longs are the same size, but ints and pointers often are not the same size on 64bit platforms. There is no "correct" way to store a 64-bit pointer in an 32-bit integer. How do I align things in the following tabular environment? That's probably going to be true for most platforms you will ever encounter, but it's not a guarantee; it's implementation-dependent. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. I need to cast the int from the first function so that I can use it as an argument for the second function. I would create a structure and pass that as void* to pthread_create. The problem was there before, you just are being notified of it. To learn more, see our tips on writing great answers. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' Why did Ukraine abstain from the UNHRC vote on China? You can use any other pointer, or you can use (size_t), which is 64 bits. Not the answer you're looking for? The cast back to int * is not, though. Bulk update symbol size units from mm to map units in rule-based symbology. If the destination type is bool, this is a boolean conversion (see below). Does ZnSO4 + H2 at high pressure reverses to Zn + H2SO4?