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

By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. However, you are also casting the result of this operation to (void*). @Martin York: No, it doesn't depend on endiannness. Terrible solution. Many errors come from warnings. In some reference type conversions, the compiler cannot determine whether a cast will be valid. Just edited. Is it safe to publish research papers in cooperation with Russian academics? The problem is not with casting, but with the target type loosing half of the pointer. 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). 4. Type Conversions - C in a Nutshell [Book] - O'Reilly Online Learning EXP36-C. Do not cast pointers into more strictly aligned pointer types 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;. ", "? This is an old C callback mechanism so you can't change that. The OP wanted to convert a pointer value to a int value, instead, most the answers, one way or the other, tried to wrongly convert the content of arg points to to a int value. Thanks for contributing an answer to Stack Overflow! With that declaration, you can later say: myData = "custom string"; That points the myData pointer to the address of your constant string. In C#, you can perform the following kinds of conversions: Implicit conversions: No special syntax is required because the conversion always succeeds and no data will be lost. c - type casting integer to void* - Stack Overflow More info about Internet Explorer and Microsoft Edge, How to convert between hexadecimal strings and numeric types, How to safely cast using pattern matching and the as and is operators. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. To learn more, see our tips on writing great answers. Converting a void* to an int is non-portable way that may work or may not! 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. 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, Short story about swapping bodies as a job; the person who hires the main character misuses his body. some reading around on it and why it is sometimes used. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. A boy can regenerate, so demons eat him for years. Thank you all for your feedback. No special syntax is necessary because a derived class always contains all the members of a base class. It's an int type guaranteed to be big enough to contain a pointer. Well it does this because you are converting a 64 bits pointer to an 32 bits integer so you loose information. Not the answer you're looking for? I'm having a little bit of trouble regarding pointer casting in my program. it often does reinterpret_cast(ptr). How a top-ranked engineering school reimagined CS curriculum (Ep. What were the most popular text editors for MS-DOS in the 1980s? Alternatively, if you choose to castthe ptr variableto (size_t) instead, then you don't need to worry about the pointer typeanymore. this question. 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. 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;. void *ptr; int n = (int)ptr; So in c++ i tried below int n = atoi (static_cast<const char*> (ptr)); This crashes when i run. And in this context, it is very very very common to see programmers lazily type cast the. For example, you might have an integer variable that you need to pass to a method whose parameter is typed as double. If we had a video livestream of a clock being sent to Mars, what would we see? Instead of using a long cast, you should cast to size_t. You can use any other pointer, or you can use (size_t), which is 64 bits. error: request for member '..' in '..' which is of non-class type. The preprocessor will replace your code by this: This is unlikely what you are trying to do. @Xax: Here's a fixed version, without the race condition: gist.github.com/depp/241d6f839b799042c409, gist.github.com/depp/3f04508a88a114734195, How a top-ranked engineering school reimagined CS curriculum (Ep. Generating points along line with specifying the origin of point generation in QGIS. To learn more, see our tips on writing great answers. Don't do that. 472,096 Members | 2,054 Online. UDF for multiples heterogenous reactions - CFD Online INT31-C. Ensure that integer conversions do not result in lost or Passing negative parameters to a wolframscript, Generating points along line with specifying the origin of point generation in QGIS. How to correctly cast a pointer to int in a 64-bit application? Typical examples include numeric conversion to a type that has less precision or a smaller range, and conversion of a base-class instance to a derived class. -1, Uggh. again. Does it effect my blogs SEO rankings? I agree that you should bite the bullet and fix the code to use the correct integer type. So reinterpret_cast has casted it to long type and then static_cast safely casts long to int, if you are ready do truncte the data. 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. 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.

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