it often does reinterpret_cast<uint32_t> (ptr). Should I re-do this cinched PEX connection? Making statements based on opinion; back them up with references or personal experience. Technically, these casts should therefore be valid. Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. X* px = new X; But to just truncate the integer value and not having to fix all the wrong uses of uint32_t just yet, you could use static_cast(reinterpret_cast(ptr)). He also rips off an arm to use as a sword, Two MacBook Pro with same model number (A1286) but different year. Keep in mind that thrArg should exist till the myFcn() uses it. rev2023.5.1.43405. Is a downhill scooter lighter than a downhill MTB with same performance? @Shahbaz you could but I will not suggest to a C newbie to use globals. You might want to typedef, You should change your code to handle this. You cannot just cast the 32-bit variable to a pointer, because that pointer on a 64-bit machine is twice as long. 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). 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;. To avoid truncating your pointer, cast it to a type of identical size. I think the solution 3> should be the correct one. Interpreting non-statistically significant results: Do we have "no evidence" or "insufficient evidence" to reject the null? Thank you all for your feedback. rev2023.5.1.43405. I hit this same problem in a project without C++11, and worked around it like this: Thanks for contributing an answer to Stack Overflow! This forum has migrated to Microsoft Q&A. Widening or Automatic Type Conversion Not the answer you're looking for? What is the difference between const int*, const int * const, and int const *? It seems both static_cast and dynamic_cast can cast a base class What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. (void *)(long)i, Copyright 2011-2023 SegmentFault. C99 defines the types "intptr_t" and "uintptr_t" which do . 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. If you convert (void*) to (long) no precision is lost, then by assigning the (long) to an (int), it properly truncates the number to fit. Not the answer you're looking for? The preprocesor absolutely will not perform arithmetic. It is possible for a cast operation that compiles correctly to fail at run time. This is why you got Error 1 C2036, from your post. For integral types, this means the range of the source type is a proper subset of the range for the target type. But to answer your question: No, you can't disable it, though you can work around it. OP said he doesn't want it. Integer conversions, both implicit and explicit (using a cast), must be guaranteed not to result in lost or misinterpreted data. The most general answer is in no way. Canadian of Polish descent travel to Poland with Canadian passport. 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. You use the address-of operator & to do that int x = 10; void *pointer = &x; And in the function you get the value of the pointer by using the dereference operator *: int y = * ( (int *) pointer); Share Improve this answer Follow edited Apr 15, 2013 at 13:58 answered Apr 15, 2013 at 13:53 Some programmer dude 396k 35 399 609 1 Asking for help, clarification, or responding to other answers. a generic module (say some ADT implementation) that requires a by: William S Fulton |
# * # (intptr_t) # # warning: cast to pointer from integer of different size # (intptr_t)IDE # (void*) . Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Can you still use Commanders Strike if the only attack available to forego is an attack against an ally? How to get the error message from the error code returned by GetLastError()? I don't see how anything bad can happen . By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Or keep using a C cast even when C++ code compiled as C++. Find centralized, trusted content and collaborate around the technologies you use most. Which was the first Sci-Fi story to predict obnoxious "robo calls"? In the following example, the compiler implicitly converts the value of num on the right to a type long before assigning it to bigNum. Yeah, the tutorial is doing it wrong. @DavidHeffernan, sane thread APIs wouldn't send integral data to the thread procedures, they would send pointers. I saw on a couple of recent posts people saying that casting the return @BlueMoon Thanks a lot! LLNL's tutorial is bad and they should feel bad. For more information, see How to convert a byte array to an int, How to convert a string to a number, and How to convert between hexadecimal strings and numeric types. I am an entry level C programmer. What would you do next year when you need to port it to yet another experimental hardware? The content you requested has been removed. How do I force make/GCC to show me the commands? However, I believe that even if the define was for the "65536", it would not be what @kaetzacoatl wanted. */void **MatrixIB (unsigned long x, unsigned long y, int size){ void *ptr; void **returnPtr; register unsigned long i, j; returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); for (i=0, j=0; j returnPtr[j] = (void *) (ptr + i); // <<< Compile Errors, Error1error C2036: 'void *' : unknown sizec:\temp\testone\lib\utils.c57, 2> returnPtr[j] = (void *) ((long*)ptr + i); // <<< No compile errors, 3> returnPtr[j] = (void *) ((char*)ptr + i); // <<< No compile errors. Usually that means the pointer is allocated with. Connect and share knowledge within a single location that is structured and easy to search. 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). Even if you are compiling your program for a 32-bit computer, you should fix your code to remove these warnings, to ensure your code is easily portable to 64-bit. So you could do this: Note: As sbi points out this would require a change on the OP call to create the thread. If the data types are compatible, then Java will perform the conversion automatically known as Automatic Type Conversion, and if not then they need to be cast or converted explicitly. a cast of which the programmer should be aware of what (s)he is doing. The proper way is to cast it to another pointer type. To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. A cast is a way of explicitly informing the compiler that you intend to make the conversion and that you are aware that data loss might occur, or the cast may fail at run time. u8 -> u32) will zero-extend if the source is unsigned sign-extend if the source is signed even though the compiler doesn't know you only ever pass myFcn to pthread_create in conjunction with an integer. For reference types, an implicit conversion always exists from a class to any one of its direct or indirect base classes or interfaces. Thanks for contributing an answer to Stack Overflow! So you know you can cast it back like this. On a 64-bit Windows computer, 'long' is a 32-bit type, and all pointers are 64-bit types. How do I check if a string represents a number (float or int)? (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, , i And, most of these will not even work on gcc4. Is a downhill scooter lighter than a downhill MTB with same performance? Does it effect my blogs SEO rankings? I've always been a little sketchy on the differences between static, 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. These kinds of operations are called type conversions. Youll be auto redirected in 1 second. How to convert a factor to integer\numeric without loss of information? Which ability is most related to insanity: Wisdom, Charisma, Constitution, or Intelligence? This is not even remotely "the correct answer". To learn more, see our tips on writing great answers. Is "I didn't think it was serious" usually a good defence against "duty to rescue"? It's always a good practice to put your #define's in brackets to avoid such surprise. User-defined conversions: User-defined conversions are performed by special methods that you can define to enable explicit and implicit conversions between custom types that do not have a base classderived class relationship. Did the drapes in old theatres actually say "ASBESTOS" on them? 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. Storage management is an important module of database, which can be subdivided into memory management and external memory management. rev2023.5.1.43405. How to force Unity Editor/TestRunner to run at full speed when in background? 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* -> integer -> void* rather than integer -> void* -> integer. Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey. Because C# is statically-typed at compile time, after a variable is declared, it cannot be declared again or assigned a value of another type unless that type is implicitly convertible to the variable's type. Extracting arguments from a list of function calls. "jacob navia" wrote: This question has probably been asked a million time, but here it comes This is an old C callback mechanism so you can't change that. 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. You are getting warnings due to casting a void* to a type of a different size. In this case, casting the pointer back to an integer is meaningless, because . Syntax static_cast< new-type > ( expression ) Returns a value of type new-type . The C Standard allows any object pointer to be cast to and from void *. 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. This is a fine way to pass integers to new pthreads, if that is what you need. Can you still use Commanders Strike if the only attack available to forego is an attack against an ally? The 32 remaining bits stored inside int are insufficient to reconstruct a pointer to the thread function. As shown in the following example, a type cast that fails at run time will cause an InvalidCastException to be thrown. Becase one can always legally cast any Hello, Is pthread_join a must when using pthread in linux? Say you hack this successfully. 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. Generating points along line with specifying the origin of point generation in QGIS. If you are going to pass the address you typically need to exert some more control over the lifetime of the object.
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