cast to 'void *' from smaller integer type 'int'

Join Bytes to post your question to a community of 472,246 software developers and data experts. With that declaration, you can later say: myData = "custom string"; That points the myData pointer to the address of your constant string. I had this error while trying to cross compile the header from libstdc++ 5.4.0 with clang 7.0.1 for ARM. He also rips off an arm to use as a sword, Two MacBook Pro with same model number (A1286) but different year. Generating points along line with specifying the origin of point generation in QGIS. 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. I have a question about casting a function pointer. equal to the original pointer: First you are using a define, which is not a variable. cast to void *' from smaller integer type 'int rev2023.5.1.43405. Could a subterranean river or aquifer generate enough continuous momentum to power a waterwheel for the purpose of producing electricity? rev2023.5.1.43405. There is absolutely not gurantee that sizeof(int) <= sizeof(void*). Find centralized, trusted content and collaborate around the technologies you use most. Should I re-do this cinched PEX connection? A. if(x%2=1)y=x;B. if(sqrt(x)%2)y=x;C. if(x==1)y=x;D. if(x==1)y=&x; Cerror: cast to 'void *' from smaller integer type 'int'. "Signpost" puzzle from Tatham's collection. C++ how to get the address stored in a void pointer? How do I work around the GCC "error: cast from SourceLocation* to int loses precision" error when compiling cmockery.c? I am using the UDF of the Ansys Manual Book as a base for what I intended, but I am trying to incorporate a second component to my condensable mixture, being methanol . i32 -> u32) is a no-op Casting from a larger integer to a smaller integer (e.g. 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). #, Nov 14 '05 Question is, how do I explain this to Clang? Casting between types - The Rust Programming Language 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". You can insert some debugging/logging logic to Reinterpret_cast if necessary. Asking for help, clarification, or responding to other answers. Episode about a group who book passage on a space ship controlled by an AI, who turns out to be a human who can't leave his ship? I guess the other important fact is that the cast operator has higher precedence that the multiplication operator. It is possible for a cast operation that compiles correctly to fail at run time. Find centralized, trusted content and collaborate around the technologies you use most. From: Hans de Goede <hdegoede@redhat.com> To: Mark Gross <mgross@linux.intel.com> Cc: Hans de Goede <hdegoede@redhat.com>, Andy Shevchenko <andy@infradead.org>, platform-driver-x86@vger.kernel.org, kernel test robot <lkp@intel.com> Subject: [PATCH] platform/x86: hp-wmi: Fix cast to smaller integer type warning Date: Mon, 23 Jan 2023 14:28:24 +0100 [thread overview] Message-ID: <20230123132824. . We have to pass address of the variable to the function because in function definition argument is pointer variable. #, In a 64 bit machine with sizeof(int) == 4. that any valid pointer to void can be converted to this type, then Connect and share knowledge within a single location that is structured and easy to search. But gcc always give me a warning, that i cannot cast an int to a void*. If you really need such trickery, then consider one of dedicated types, which are intptr_t and uintptr_t. this way I convert an int to a void* which is much better than converting a void* to an int. As a result, it is possible to silently convert from one pointer type to another without the compiler diagnosing the problem by storing or casting a pointer to void * and then storing or casting it to the final type. You can use any other pointer, or you can use (size_t), which is 64 bits. I cannot reverse my upvote of user384706's answer, but it's wrong. u8 -> u32) will zero-extend if the source is unsigned sign-extend if the source is signed Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. If the result lies outside the range of representable values by the type, the conversion causes, Otherwise, if the conversion is between numeric types of the same kind (integer-to-integer or floating-to-floating), the conversion is valid, but the value is. rev2023.5.1.43405. I agree that you should bite the bullet and fix the code to use the correct integer type. last post by: I'm looking for the name of the following casting style in order to do Windows has 32 bit long only on 64 bit as well. @jackdoe: It's a waste of human life to write code that "you may need in the future". Did the Golden Gate Bridge 'flatten' under the weight of 300,000 people in 1987? Your strategy will not work for stack-allocated objects, be careful!! 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). To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. It seems both static_cast and dynamic_cast can cast a base class Is "I didn't think it was serious" usually a good defence against "duty to rescue"? @DietrichEpp can you explain what is race condition with using. Did the drapes in old theatres actually say "ASBESTOS" on them? Folder's list view has different sized fonts in different folders. There exist two main syntaxes for generic type-casting: functional and c-like: 1 2 3 4 double x = 10.3; int y; y = int (x); // functional notation y = (int) x; // c-like cast notation The functionality of these generic forms of type-casting is enough for most needs with fundamental data types. Can you still use Commanders Strike if the only attack available to forego is an attack against an ally? This is why you got Error 1 C2036, from your post. 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. Has the cause of a rocket failure ever been mis-identified, such that another launch failed due to the same problem? This is not a conversion at all. ", "!"? If a negative integer value is converted to an unsigned type, the resulting value corresponds to its 2's complement bitwise representation (i.e., If the conversion is from a floating-point type to an integer type, the value is truncated (the decimal part is removed). Losing bytes like thisis called 'truncation', and that's what the first warning is telling you. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. When is casting void pointer needed in C? How do I check if a string represents a number (float or int)? This is an old C callback mechanism so you can't change that. Can my creature spell be countered if I cast a split second spell after it? for saving RAM), use union, and make sure, if the mem address is treated as an int only if you know it was last set as an int. to the original pointer: The following type designates an unsigned integer type with the # * # (intptr_t) # # warning: cast to pointer from integer of different size # (intptr_t)IDE # (void*) . C / C++ Forums on Bytes. c - Cast int to void* - Stack Overflow One could try -fms-extensions (hopefully not -fms-compatibility), but that would bring all the shebang with it. Storage management is an important module of database, which can be subdivided into memory management and external memory management. Then he wants to convert px to Hello, "I think what you should do is actually pass the address of the variable to the function" Not necessarily. Not the answer you're looking for? Why does Acts not mention the deaths of Peter and Paul? is there such a thing as "right to be heard"? So,solution #3 works just fine. Embedded hyperlinks in a thesis or research paper. How a top-ranked engineering school reimagined CS curriculum (Ep. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, I would try to fix the code instead. Does a password policy with a restriction of repeated characters increase security? 472,096 Members | 2,054 Online. Most answers just try to extract 32 useless bits out of the argument. The semantics of numeric casts are: Casting between two integers of the same size (e.g. The 32 remaining bits stored inside int are insufficient to reconstruct a pointer to the thread function. 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. Why does Acts not mention the deaths of Peter and Paul? But this code pass the normal variable .. Thanks for contributing an answer to Stack Overflow! The error I'm getting is: error: cast from pointer to smaller type 'uint32_t' (aka 'unsigned int') loses information. arrays - I get the error: "cast to smaller integer type 'int' from What is this brick with a round back and a stud on the side used for? Infact I know several systems where that does not hold. MIP Model with relaxed integer constraints takes longer to solve than normal model, why? returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); Asking for help, clarification, or responding to other answers. Yes, for the reason you mentioned that's the proper intermediate type. Why are players required to record the moves in World Championship Classical games? Terrible solution. This thread has been closed and replies have been disabled. casting from int to void* and back to int. I am an entry level C programmer. how about using uintptr_t, most of your pointer arithmetic may still works. Connect and share knowledge within a single location that is structured and easy to search. Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. Casting a pointer to void* and back is valid use of reinterpret_cast<>. He should pass the address of the integer, the thread should get that address, Note: This is only appropriate is you cast the. For built-in numeric types, an implicit conversion can be made when the value to be stored can fit into the variable without being truncated or rounded off. Why did US v. Assange skip the court of appeal? 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. c - How to cast an integer to void pointer? - Stack Overflow To access the object value, use the * dereference operator: int * p; assert (p == null ); p = new int (5); assert (p != null ); assert (*p == 5); (*p)++; assert (*p == 6); If a pointer contains a null value, it is not pointing to a valid object. The error message mentions the diagnostic responsible for error message, e.g. For example, (double) 1/3 will give a double result instead of an int one. Which ability is most related to insanity: Wisdom, Charisma, Constitution, or Intelligence? If any, how can the original function works without errors if we just ignore the warning. Casting arguments inside the function is a lot safer. That could create all kinds of trouble. cwindowccwindowsword[3]={"ab"};_ab charPersondebug, A, A, , "C" ???? 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. Since the culprit is probably something like -Wall which enables many warnings you should keep on, you should selectively disable this single warning. (void *)(long)i, Copyright 2011-2023 SegmentFault. return ((void **) returnPtr);} /* Matrix() */. For more information, see the Conversions section of the C# language specification. Syntax static_cast< new-type > ( expression ) Returns a value of type new-type . But to answer your question: No, you can't disable it, though you can work around it. Please start a new discussion. 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. INT31-C. Ensure that integer conversions do not result in lost or MIP Model with relaxed integer constraints takes longer to solve than normal model, why? Is a downhill scooter lighter than a downhill MTB with same performance? Instead of using a long cast, you should cast to size_t. Remembering to delete the pointer after use so that we don't leak. this way you won't get any warning. Again, all of the answers above missed the point badly. Since the 'size' argument for your function is the number of bytes each element in the array needs, I think casting the pointerto (char*) is appropriate. For example, if the pointers in a system are stored in 16 bits, but integers are stored in 8 bits, a total of 8 bits would be lost in the . This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s). 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. Definition: C++ introduced a different cast system from C that distinguishes the types of cast operations. I don't see how anything bad can happen . Unfortunately, that hardware is 64-bit and the code contains many instances of pointer arithmetic that expects pointers to be 32-bit, i.e. Making statements based on opinion; back them up with references or personal experience. Thanks for contributing an answer to Stack Overflow! Implicit conversions - cppreference.com They should do their job unless your code is too tricky. This is memory reinterpretation - a completely unacceptable way to do what the OP is trying to do. Expressions Converts between types using a combination of implicit and user-defined conversions. pthread create managing values generated in function (in c), Establishing TCP socket connection between PHP client and C server on Ubuntu. As shown in the following example, a type cast that fails at run time will cause an InvalidCastException to be thrown. Interpreting non-statistically significant results: Do we have "no evidence" or "insufficient evidence" to reject the null? If you do this, you have the thread reference a value that (hopefully still) lives in some other thread. Which was the first Sci-Fi story to predict obnoxious "robo calls"? I think the solution 3> should be the correct one. [PATCH] platform/x86: hp-wmi: Fix cast to smaller integer type warning Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey, error: cast from void* to int loses precision, cast to pointer from integer of different size, pthread code. 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.

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