Pd = Pa; Similarly, Pc may be type cast to type int and assigned the value Pa. 1. rev2023.3.3.43278. Please help me compile Chez Scheme. To learn more, see our tips on writing great answers. Why is this sentence from The Great Gatsby grammatical? with ids being an array of ints and touch being a pointer. Well occasionally send you account related emails. You are getting warnings due to casting a void* to a type of a different size. Functions return bigint only if the parameter expression is a bigint data type. You are getting warnings due to casting a void* to a type of a different size. Why do academics stay as adjuncts for years rather than move around? Can Martian regolith be easily melted with microwaves? For the second example you can make sure that sizeof (int) <= sizeof (void *) by using a static_assert -- this way at least you'll get a notice about it. [that could be a TODO - not to delay solving the ICE]. Is it possible to create a concave light? ../lib/odp-util.c:5601:9: note: expanded from macro 'SCAN_PUT' By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. This explicit cast clearly tells the compiler "Shut up, I know that this code does not look correct, but I do know what I am doing". Bulk update symbol size units from mm to map units in rule-based symbology. Converting a pointer to an integer whose result cannot represented in the integer type is undefined behavior is C and prohibited in C++. Notifications. 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). 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. Using Kolmogorov complexity to measure difficulty of problems? On most platforms pointers and longs are the same size, but ints and pointers often are not the same size on 64bit platforms. Pull requests. If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. I think the solution 3> should be the correct one. 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;. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. @BlueMoon Thanks a lot! By clicking Sign up for GitHub, you agree to our terms of service and I'm trying to create a void* from an int. ^~~~~~~~~~~~~~~~~~~~~ If not, check the pointer size on your platform, define these typedefs accordingly yourself and use them. 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. "-I.." "-Iinclude\openflow" "-I..\include\openflow" "-Iinclude\openvswitch" "-I..\include\openvsw He should pass the address of the integer, the thread should get that address, Note: This is only appropriate is you cast the. In both cases, converting the pointer to an integer type that's too small to represent all pointer values is a bug. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul Typically, long or unsigned long is . byte -> short -> char -> int -> long -> float -> double. error: comparison between pointer and integer ('int' and 'string' (aka 'char *')), CS50 Caesar program is working but check50 says it isn't. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Usually that means the pointer is allocated with. A missing cast in the new fast > enumeration code. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? // OK: lvalue denoting the original d object, // UB: the b subobject is not a base class subobject, // 6. array-to-pointer followed by upcast, https://en.cppreference.com/mwiki/index.php?title=cpp/language/static_cast&oldid=147983, when converting a 'pointer to object' to 'pointer to, the conversion from floating-point values, the conversion from bit-fields to rvalue references, the conversion from integral or enumeration values to enumeration, the conversion from integral or enumeration values to, the conversion from a member of base class type to, a standard-layout class object with no data members, a non-standard-layout union object and a non-static data, for base-to-derived pointer conversions and, the conversion to enumeration types with fixed underlying type, a standard-layout class might have a non-pointer-interconvertible, If the underlying type is not fixed, the behavior is undefined if the value of, If the underlying type is fixed, the result is the same as, one is a union object and the other is a non-static data member of that object, or. 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. rev2023.3.3.43278. In such condition type conversion (type promotion) takes place to avoid loss of data. "After the incident", I started to be more careful not to trip over things. rev2023.3.3.43278. How can this new ban on drag possibly be considered constitutional? No idea how it amassed 27 upvotes?! You need to pass an actual pointer. On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. You can only do this if you use a synchronization primitive to ensure that there is no race condition. This is not even remotely "the correct answer". If pointers are 64 bits and ints are 32 bits, an int is too small to hold a pointer value. The main point is: a pointer has a platform dependent size. A cast converts an object or value from one type to another. 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. Terrible solution. Have a question about this project? Since gcc compiles that you are performing arithmetic between void* and an int (1024). 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. Safe downcast may be done with dynamic_cast. @DavidHeffernan I rephrased that sentence a little. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Any expression can be cast to type void (which means that the result of the expression is ignored), but it's not legal to cast an expression of type void to type int not least because the result of such a cast wouldn't make any sense. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Keep in mind that thrArg should exist till the myFcn() uses it. Use returnPtr[j] = (void *) ((long)ptr + i); ). This solution is in accordance with INT18-C. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. Not the answer you're looking for? "-D_FILE_OFFSET_BITS=64" "-Wall" "-Winvalid-pch" "-g" "-Wthread-safety" "-Wno-microsoft-enum-forward-reference" "-Wno-unused-function" "-Wno-sometimes-unini Infact I know several systems where that does not hold. 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. 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). Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Thanks for contributing an answer to Stack Overflow! The difference between the phonemes /p/ and /b/ in Japanese, Styling contours by colour and by line thickness in QGIS, AC Op-amp integrator with DC Gain Control in LTspice, Identify those arcade games from a 1983 Brazilian music video. To learn more, see our tips on writing great answers. Thanks for contributing an answer to Stack Overflow! By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 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. Noncompliant Code Example (memset())For historical reasons, certain C Standard functions accept an argument of type int and convert it to either unsigned char or plain char. I have the following function and when I compile it under VS.NET 2005, the following compile warnings show up: Warning1warning C4311: 'type cast' : pointer truncation from 'void *' to 'long'c:\temp\testone\lib\utils.c56Warning2warning C4312: 'type cast' : conversion from 'unsigned long' to 'void *' of greater sizec:\temp\testone\lib\utils.c56, Code Snippet Mutually exclusive execution using std::atomic? 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. If the sizes are different then endianess comes into play. The 32 remaining bits stored inside int are insufficient to reconstruct a pointer to the thread function. 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. casting from int to void* and back to int. Then i can continue compiling. To learn more, see our tips on writing great answers. That could create all kinds of trouble. Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. Next, when doing pointer arithmetic, the addition operation will use the pointer's type to determine how many bytes to add to it when incrementing it. You are correct, but cocos actually only uses that address as a unique id. static_cast on the other hand should deny your stripping away the const qualifier. 1. So,solution #3 works just fine. ../lib/odp-util.c:5658:9: note: expanded from macro 'SCAN_END_SINGLE' Why do small African island nations perform better than African continental nations, considering democracy and human development? C/C++ , Cerror: cast to 'void *' from smaller integer type 'int'. 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. reinterpret_cast is a type of casting operator used in C++. Asking for help, clarification, or responding to other answers. It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. 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; Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Making statements based on opinion; back them up with references or personal experience. Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, "what happen when typcating normal variable to void* or any pointer variable?" ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? You are right! lexborisov Modest Public. Not the answer you're looking for? LLNL's tutorial is bad and they should feel bad. If the function had the correct signature you would not need to cast it explicitly. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ While working with Threads in C, I'm facing the warning, "warning: cast to pointer from integer of different size". Identify those arcade games from a 1983 Brazilian music video. Most answers just try to extract 32 useless bits out of the argument. @jackdoe: It's a waste of human life to write code that "you may need in the future". Casting arguments inside the function is a lot safer. Connect and share knowledge within a single location that is structured and easy to search. Bulk update symbol size units from mm to map units in rule-based symbology. What does it mean to convert int to void* or vice versa? Thanks for pointing that out. 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). Mutually exclusive execution using std::atomic? AC Op-amp integrator with DC Gain Control in LTspice. Does Counterspell prevent from any further spells being cast on a given turn? To be honest, I think, clang is too restrictive here. Don't do that. How do I force make/GCC to show me the commands? itch" "-I..\include\windows" "-Iinclude" "-I..\include" "-I..\datapath-windows\include" "-IC:\PTHREADS-BUILT\include" "-Xclang" "-fcolor-diagnostics" "-pipe" As a result of the integer division 3/2 we get the value 1, which is of the int type. Whats the grammar of "For those whose stories they are"? @DavidHeffernan, sane thread APIs wouldn't send integral data to the thread procedures, they would send pointers. even though the compiler doesn't know you only ever pass myFcn to pthread_create in conjunction with an integer. I'm using cocos2d-x-2.2.2. Again, all of the answers above missed the point badly. From the question I presume the OP does. Sign in long guarantees a pointer size on Linux on any machine. (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 Identify those arcade games from a 1983 Brazilian music video, Relation between transaction data and transaction id, The difference between the phonemes /p/ and /b/ in Japanese. The pointer doesn't actually point to anything, but it's the result of an earlier cast from an integer to a pointer (e.g. Anw, the project still build and run normally when i use Xcode 5.0 with iOS 7.0. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. (Also, check out how it prints "5" twice), passing a unique pointer to each thread wont race, and you can get/save any kind of information in the th struct. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. How do I check if a string represents a number (float or int)? The value of float variable is= 37.75. 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. 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. Implementing From will result in the Into implementation but not vice-versa. Even though what you say regarding the lifetime of the object is true, integral types are too limited for a generic API. Therefore, you need to change it to long long instead of long in windows for 64 bits. ../lib/odp-util.c:5489:33: note: expanded from macro 'SCAN_PUT_ATTR'