cast to void *' from smaller integer type 'int

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). Asking for help, clarification, or responding to other answers. "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. Why does Mister Mxyzptlk need to have a weakness in the comics? Infact I know several systems where that does not hold. @DavidHeffernan, sane thread APIs wouldn't send integral data to the thread procedures, they would send pointers. I need to cast the int from the first function so that I can use it as an argument for the second function. 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. pthread create managing values generated in function (in c), Establishing TCP socket connection between PHP client and C server on Ubuntu. The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Connect and share knowledge within a single location that is structured and easy to search. vegan) just to try it, does this inconvenience the caterers and staff? How to correctly cast a pointer to int in a 64-bit application? It generally takes place when in an expression more than one data type is present. If you need to keep the returned address, just keep it as void*. There is absolutely not gurantee that sizeof(int) <= sizeof(void*). Thanks. 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. 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. whether it was an actual problem is a different matter though. rev2023.3.3.43278. What video game is Charlie playing in Poker Face S01E07? An open (void) pointer can hold a pointer of any type. Issues. 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. 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. And, most of these will not even work on gcc4. This page was last modified on 12 February 2023, at 18:25. If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. LLNL's tutorial is bad and they should feel bad. This is what the second warning is telling you. You are getting warnings due to casting a void* to a type of a different size. Making statements based on opinion; back them up with references or personal experience. It is done by the compiler on its own, without any external trigger from the user. But, sure, in that specific case you can pass a local variable address, type casting integer to void* [duplicate]. I'm trying to learn pthreads and thing that keeps bugging me is how do i really pass argument to the function. rev2023.3.3.43278. From that point on, you are dealing with 32 bits. Converting a pointer to an integer whose result cannot represented in the integer type is undefined behavior is C and prohibited in C++. 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 main point is: a pointer has a platform dependent size. Why is there a voltage on my HDMI and coaxial cables? ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~. Once you manage to make this cast, then what?! I have a two functions, one that returns an int, and one that takes a const void* as an argument. 1. To learn more, see our tips on writing great answers. Update: Today, i download the latest version of cocos2d-x (cocos2d-x 2.2.3). If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. equal to the original pointer: First you are using a define, which is not a variable. warning C4311: 'type cast': pointer truncation from 'void *' to 'long' in ECPG test files. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. This will get you a pointer from a 32 bit offset: A function pointer is incompatible to void* (and any other non function pointer). 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. pthread passes the argument as a void*. 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. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. Then I build my project, I get the error "Cast from pointer to smaller type 'int' loses information" in EAGLView.mm file (line 408) when 64-bit simulators (e.g. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? 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. Disconnect between goals and daily tasksIs it me, or the industry? So,solution #3 works just fine. Connect and share knowledge within a single location that is structured and easy to search. Can Martian regolith be easily melted with microwaves? ), Styling contours by colour and by line thickness in QGIS. Getting Command /bin/sh failed with exit code 65 Error with Xcode 5.1 . If your standard library (even if it is not C99) happens to provide these types - use them. To learn more, see our tips on writing great answers. This will only compile if the destination type is long enough. You are getting warnings due to casting a void* to a type of a different size. @Artelius: Which, presumably, is exactly what Joshua did: A C++ reinterpret cast will not solve the problem. You can use any other pointer, or you can use (size_t), which is 64 bits. Implementing From will result in the Into implementation but not vice-versa. He should pass the address of the integer, the thread should get that address, Note: This is only appropriate is you cast the. ../lib/odp-util.c:5603:13: note: expanded from macro 'SCAN_PUT' The proper way is to cast it to another pointer type. Even though what you say regarding the lifetime of the object is true, integral types are too limited for a generic API. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. 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. ), For those who are interested. It is commonly called a pointer to T and its type is T*. Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ It's an int type guaranteed to be big enough to contain a pointer. How to convert a factor to integer\numeric without loss of information? Then i can continue compiling. ", "? This solution is in accordance with INT18-C. Thanks for pointing that out. Can I tell police to wait and call a lawyer when served with a search warrant? A missing cast in the new fast > enumeration code. Windows has 32 bit long only on 64 bit as well. this question. Therefore, you need to change it to long long instead of long in windows for 64 bits. Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. . 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. 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 . Notifications. In Java, there are two types of casting: Widening Casting (automatically) - converting a smaller type to a larger type size. 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. 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. This returns the first 32 bits of the pointer which may be the top or the bottom depending on big versus little endian, as comment #2 said. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. In both cases, converting the pointer to an integer type that's too small to represent all pointer values is a bug. Cast characters to unsigned char before converting to larger integer sizes Created by Robert Seacord, last modified by Jill Britton on Oct 03, 2022 Signed character data must be converted to unsigned char before being assigned or converted to a larger signed type. If the sizes are different then endianess comes into play. Asking for help, clarification, or responding to other answers. Why is there a voltage on my HDMI and coaxial cables? Keep in mind that thrArg should exist till the myFcn() uses it. 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 plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Don't do that. The value of float variable is= 37.75. @jackdoe: It's a waste of human life to write code that "you may need in the future". "-D_FILE_OFFSET_BITS=64" "-Wall" "-Winvalid-pch" "-g" "-Wthread-safety" "-Wno-microsoft-enum-forward-reference" "-Wno-unused-function" "-Wno-sometimes-unini and how to print the thread id of 2d array argument? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Dinesh: could you please 1) show us those. void* -> integer -> void* rather than integer -> void* -> integer. Asking for help, clarification, or responding to other answers. The correct answer is, if one does not mind losing data precision. Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. That could create all kinds of trouble. 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. Find centralized, trusted content and collaborate around the technologies you use most. The result is implementation-defined and typically yields the numeric address of the byte in memory that the pointer pointers to. Recovering from a blunder I made while emailing a professor. Difficulties with estimation of epsilon-delta limit proof. I usually have all automatic conversion warnings effective when developing in C, and I use explicit casting in order to suppress a specific . Casting arguments inside the function is a lot safer. The text was updated successfully, but these errors were encountered: You signed in with another tab or window. /** Dynamically allocate a 2d (x*y) array of elements of size _size_ bytes. So you know you can cast it back like this. ../lib/odp-util.c:5665:7: note: expanded from macro 'SCAN_SINGLE' Thanks for contributing an answer to Stack Overflow!

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