@Shahbaz you could but I will not suggest to a C newbie to use globals. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? It is done by the compiler on its own, without any external trigger from the user. 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. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? All character types are to be converted to an integer. 7.1 New Cast Operations The C++ standard defines new cast operations that provide finer control than previous cast operations. Put your define inside a bracket: without a problem. ncdu: What's going on with this second size column? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. You can convert the values from one type to another explicitly using the cast operator as follows (type_name) expression privacy statement. If this is the data to a thread procedure, then you quite commonly want to pass by value. Java Type Casting - W3Schools Typically, long or unsigned long is . SQL Server does not automatically promote . B Programming Language | What is the History and Concept? The problem just occur with Xcode 5.1. What is the purpose of non-series Shimano components? In this case, casting the pointer back to an integer is meaningless, because . What is the difference between const int*, const int * const, and int const *? Is pthread_join a must when using pthread in linux? The cast back to int * is not, though. Casting int to void* : r/C_Programming - reddit 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. Therefore, you need to change it to long long instead of long in windows for 64 bits. Why do small African island nations perform better than African continental nations, considering democracy and human development? The value of float variable is= 37.75. 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 way I convert an int to a void* which is much better than converting a void* to an int. Before I update Xcode, my project still can build and run normally with all devices. warning C4311: 'type cast': pointer truncation from 'void *' to 'long' in ECPG test files. By clicking Sign up for GitHub, you agree to our terms of service and How to correctly type cast (void*)? - social.msdn.microsoft.com 4. Type Conversions - C in a Nutshell [Book] - O'Reilly Online Learning 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. However the actual code in question contains an explicit c-style cast to int. I guess the other important fact is that the cast operator has higher precedence that the multiplication operator. 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. This is not a conversion at all. iphone - Error "Cast from pointer to smaller type 'int' loses 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. Converting a pointer to an integer whose result cannot represented in the integer type is undefined behavior is C and prohibited in C++. Not the answer you're looking for? Casting arguments inside the function is a lot safer. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. But the problem has still happened. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? 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 . Use of Void pointers in C programming language For example, the main thread could wait for all of the other threads to end before terminating. 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. Disconnect between goals and daily tasksIs it me, or the industry? This is a fine way to pass integers to new pthreads, if that is what you need. Re: [PATCH, PR 53001] Re: Patch to split out new warning flag for Now, what happens when I run it with the thread sanitizer? There is no "correct" way to store a 64-bit pointer in an 32-bit integer. But I'm nitpicking .. Find centralized, trusted content and collaborate around the technologies you use most. 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. Is it possible to create a concave light? What you do here is undefined behavior, and undefined behavior of very practical sort. Where does this (supposedly) Gibson quote come from? I am an entry level C programmer. In such condition type conversion (type promotion) takes place to avoid loss of data. Can I tell police to wait and call a lawyer when served with a search warrant? You are right! Is a PhD visitor considered as a visiting scholar. How to correctly cast a pointer to int in a 64-bit application? This solution is in accordance with INT18-C. 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). You may declare a const int variable and cast its reference to the void*. should we also have a diagnostic for the (presumed) user error? long guarantees a pointer size on Linux on any machine. If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. Safe downcast may be done with dynamic_cast. 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 is there a voltage on my HDMI and coaxial cables? I have a two functions, one that returns an int, and one that takes a const void* as an argument. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? How to use Slater Type Orbitals as a basis functions in matrix method correctly? 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. 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. 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! 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. Type casting is when you assign a value of one primitive data type to another type. If int is no larger than pointer to void then one way to store the value is by simply copying the bytes: int i . 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. You are correct, but cocos actually only uses that address as a unique id. 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. Thanks for contributing an answer to Stack Overflow! It's an int type guaranteed to be big enough to contain a pointer. vegan) just to try it, does this inconvenience the caterers and staff? Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Narrowing Casting (manually) - converting a larger type to a . A nit: in your version, the cast to void * is unnecessary. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? 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. I agree passing a dynamically allocated pointer is fine (and I think the best way). No sense in writing a few dozen lines of extra code just to get a bunch of numbered threads. BUT converting a pointer to void* and back again is well supported (everywhere). He should pass the address of the integer, the thread should get that address, Note: This is only appropriate is you cast the. 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). Any help with this is appreciated. 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 Click to see the query in the CodeQL repository. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? Casting type int to const void* - C / C++ 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)). Type Casting in C Language with Examples - Dot Net Tutorials Create an account to follow your favorite communities and start taking part in conversations. You can use any other pointer, or you can use (size_t), which is 64 bits. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. You are getting warnings due to casting a void* to a type of a different size. 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. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul 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. C99 defines the types "intptr_t" and "uintptr_t" which do . If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. Implicit Type Conversion in C with Examples - GeeksforGeeks [mst-vhost:vhost 5/52] drivers/block/virtio_blk.c:539:21: warning 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. reinterpret_cast is a type of casting operator used in C++. 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. 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. C / C++ Forums on Bytes. then converted back to pointer to void, and the result will compare If you need to keep the returned address, just keep it as void*. Keep in mind that thrArg should exist till the myFcn() uses it. Yeah, the tutorial is doing it wrong. 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. [Solved] Error "Cast from pointer to smaller type 'int' | 9to5Answer Java Type Casting. ../lib/odp-util.c:5603:13: note: expanded from macro 'SCAN_PUT' Have a question about this project? eg. Surely the solution is to change the type of ids from int to type that is sufficiently large to hold a pointer. To avoid truncating your pointer, cast it to a type of identical size. 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). The problem is not with casting, but with the target type loosing half of the pointer. If the sizes are different then endianess comes into play. ncdu: What's going on with this second size column? 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). A cast converts an object or value from one type to another. That's probably going to be true for most platforms you will ever encounter, but it's not a guarantee; it's implementation-dependent. you can just change architecture to support 32 bit compilation by all below in in Build Settings. The program can be set in such a way to ask the user to inform the type of data and . By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. rev2023.3.3.43278. But then you need to cast your arguments inside your thread function which is quite unsafe cf. @BlueMoon Thanks a lot! @DavidHeffernan I rephrased that sentence a little. It solved my problem too. Whats the grammar of "For those whose stories they are"?