Connect and share knowledge within a single location that is structured and easy to search. SCAN_PUT(ATTR, NULL); What is the point of Thrower's Bandolier? The high-order 9 bits of the number are used to hold a flag value, and the result is converted back into a pointer. Or, they are all wrong. Your first example is risky because you have to be very careful about the object lifetimes. Since gcc compiles that you are performing arithmetic between void* and an int (1024). Thanks for pointing that out. The point is (probably) that the value passed to the thread is an integer value, not really a 'void *'. Instead of using a long cast, you should cast to size_t. to the original pointer: The following type designates an unsigned integer type with the 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). There is no "correct" way to store a 64-bit pointer in an 32-bit integer. this way you won't get any warning. Put your define inside a bracket: without a problem. In the best case this will give the same results as the original code, with no advantages, but in the worst case it will fail in multiple catastrophic ways (type punning, endianness, less efficient, etc. Please tell me error: cast from 'void*' to 'int' loses precision, How Intuit democratizes AI development across teams through reusability. If the original pointer value represents an address of a byte in memory that does not satisfy the alignment requirement of the target type, then the resulting pointer value is unspecified. It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. He should pass the address of the integer, the thread should get that address, Note: This is only appropriate is you cast the. should we also have a diagnostic for the (presumed) user error? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Dinesh: could you please 1) show us those. I am an entry level C programmer. Making statements based on opinion; back them up with references or personal experience. windows meson: cast to smaller integer type 'unsigned long' from 'void *'. How to correctly cast a pointer to int in a 64-bit application? How to notate a grace note at the start of a bar with lilypond? ), Styling contours by colour and by line thickness in QGIS. Do new devs get fired if they can't solve a certain bug? 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. Why does Mister Mxyzptlk need to have a weakness in the comics? If your standard library (even if it is not C99) happens to provide these types - use them. ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. @DavidHeffernan I rephrased that sentence a little. Error while setting app icon and launch image in xcode 5.1. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. eg. I need to cast the int from the first function so that I can use it as an argument for the second function. 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. 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". This is known as implicit type casting or type promotion, compiler automatically converts smaller data type to larger data type. No idea how it amassed 27 upvotes?! As for the stack, I've written a few libraries using pthreds, thus I don't agree that what you describe "is quite often the case". rev2023.3.3.43278. "-I.." "-Iinclude\openflow" "-I..\include\openflow" "-Iinclude\openvswitch" "-I..\include\openvsw Find centralized, trusted content and collaborate around the technologies you use most. 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. 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). Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? It is commonly called a pointer to T and its type is T*. Asking for help, clarification, or responding to other answers. Implicit Type Conversion is also known as 'automatic type conversion'. 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. 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. Find centralized, trusted content and collaborate around the technologies you use most. 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 Sign in The result is implementation-defined and typically yields the numeric address of the byte in memory that the pointer pointers to. A cast specifies a conversion from one type to another. ^~~~~~~~~~~~~~~~~~~~~ How do I check if a string represents a number (float or int)? 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. error: cast from pointer to smaller type 'unsigned int' loses information. This is what the second warning is telling you. Narrowing Casting (manually) - converting a larger type to a . 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). This solution is in accordance with INT18-C. Find centralized, trusted content and collaborate around the technologies you use most. How do I set, clear, and toggle a single bit? I have a two functions, one that returns an int, and one that takes a const void* as an argument. Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul Well it does this because you are converting a 64 bits pointer to an 32 bits integer so you loose information. Basically its a better version of (void *)i. what does it mean to convert int to void* or vice versa? STR34-C. All float types are to be converted to double. So,solution #3 works just fine. (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 /** Dynamically allocate a 2d (x*y) array of elements of size _size_ bytes. Implementing From will result in the Into implementation but not vice-versa. 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; rev2023.3.3.43278. equal to the original pointer: First you are using a define, which is not a variable. Changing the type of ids would be the cleanest solution, but I decided against it when being confronted with this issue myself, as it only introduced a lot of issues with other code that is relying on ids being an int-array. If the object expression refers or points to is actually a base class subobject of an object of type D, the result refers to the enclosing object of type D. Otherwise, the behavior is undefined: When the target type is bool (possibly cv-qualified), the result is false if the original value is zero and true for all other values. What you do here is undefined behavior, and undefined behavior of very practical sort. 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. "-D_FILE_OFFSET_BITS=64" "-Wall" "-Winvalid-pch" "-g" "-Wthread-safety" "-Wno-microsoft-enum-forward-reference" "-Wno-unused-function" "-Wno-sometimes-unini If the original type is a void *, converting to an int may lose date on platforms where sizeof(void *) != sizeof(int) (which is true of LP64 programming model). How can this new ban on drag possibly be considered constitutional? In such a case the programmer can use a void pointer to point to the location of the unknown data type. But you seem to suggest by your answer that the user can pass 5 to pthread_create and then perform the above cast to get it back. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? For example, the main thread could wait for all of the other threads to end before terminating. Can I tell police to wait and call a lawyer when served with a search warrant? 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). I think the solution 3> should be the correct one. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. what does it mean to convert int to void* or vice versa? rev2023.3.3.43278. SQL Server does not automatically promote . Yeah, the tutorial is doing it wrong. *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 . What is the purpose of non-series Shimano components? The main point is: a pointer has a platform dependent size. Acidity of alcohols and basicity of amines. Anw, the project still build and run normally when i use Xcode 5.0 with iOS 7.0.
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