Types - D Programming Language Please unaccept the answer you have chosen as it is wrong (as the comments below it say) and will lead to bugs. Cerror: cast to 'void *' from smaller integer type 'int' Just re-enforcing the old behavior of Xcode 5.0 and earlier versions, that already cut away parts of the address by casting it to int, won't introduce any new bugs and avoids the need to learn and understand lots of implementation-internal cocos code. unsigned long call_fn = (unsigned long)FUNC; As a result of the integer division 3/2 we get the value 1, which is of the int type. ../lib/odp-util.c:5489:33: note: expanded from macro 'SCAN_PUT_ATTR' It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. should we also have a diagnostic for the (presumed) user error? ^~~~~~~~~~~~~~~~~~~~ If you preorder a special airline meal (e.g. How can this new ban on drag possibly be considered constitutional? And, most of these will not even work on gcc4. Does Counterspell prevent from any further spells being cast on a given turn? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. windows meson: cast to smaller integer type 'unsigned long' from 'void *'. Just edited. Mutually exclusive execution using std::atomic? Well occasionally send you account related emails. Bulk update symbol size units from mm to map units in rule-based symbology. If it's anything like cocos2d-iphone v2.x and just based on this slice of code in a core class I wager it's safe to say that cocos2d-x 2.x also is not compatible with 64 bit code, and you can expect all kinds of issues (not just compile-time but also runtime). Properly casting a `void*` to an integer in C++ 24,193 Solution 1 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. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? Cast Operations - Oracle But the problem has still happened. Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. Press question mark to learn the rest of the keyboard shortcuts. Then i can continue compiling. 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. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Can I tell police to wait and call a lawyer when served with a search warrant? 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. int, bigint, smallint, and tinyint (Transact-SQL) - SQL Server Is a PhD visitor considered as a visiting scholar. Taking the above declarations of A, D, ch of the . Have a question about this project? 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. cast operators [edit] When an expression is used in the context where a value of a different type is expected, conversionmay occur: intn =1L;// expression 1L has type long, int is expectedn =2.1;// expression 2.1 has type double, int is expectedchar*p =malloc(10);// expression malloc(10) has type void*, char* is expected Since all pointers on 64-bit Windows are 64 bits, you are growing the data size from 32 bits backto 64 bits. I cannot reverse my upvote of user384706's answer, but it's wrong. The problem is not with casting, but with the target type loosing half of the pointer. How to correctly cast a pointer to int in a 64-bit application? 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. */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. You use the address-of operator & to do that. Don't do that. This allows you to reinterpret the void * as an int. 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). Replacing broken pins/legs on a DIP IC package, AC Op-amp integrator with DC Gain Control in LTspice. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. The code ((void*)ptr + 1) does not work, because the compiler has no idea what size "void" is, and therefore doesn't know how many bytes to add. I am compiling this program in linux gcc compiler.. An object pointer (including void*) or function pointer can be converted to an integer type using reinterpret_cast. 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. 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. My code is all over the place now but I appreciate you all helping me on my journey to mastery! The cast back to int * is not, though. And when assigning to a void pointer, all type information is lost. A pointer converted to an integer of sufficient size and back to the same pointer type is guaranteed to have its original value, otherwise the resulting pointer cannot be dereferenced safely ( the round-trip conversion in the opposite direction is not guaranteed [.]) Why is there a voltage on my HDMI and coaxial cables? Already on GitHub? Casting type void to uint8_t - Arduino Forum 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. ncdu: What's going on with this second size column? 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. Use returnPtr[j] = (void *) ((long)ptr + i); ). In simple example code like this it's very easy to convince yourself that there's no problem, but in more elaborate real-world scenarios it's very easy to make this mistake inadvertently. warning C4311: 'type cast': pointer truncation from 'void *' to 'long' in ECPG test files. Create an account to follow your favorite communities and start taking part in conversations. In the first example, the variable c1 of the char type is converted to a temporary variable of the int type, because the second operand in the division operation, the constant 2, is of the higher type int. use $(ARCHS_STANDARD_32_BIT) at Architecture instead of $(ARCHS_STANDARD). 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. reinterpret_cast is a type of casting operator used in C++. Now, what happens when I run it with the thread sanitizer? Otherwise, if the original pointer value points to an object a, and there is an object b of the . I assumed that gcc makes a 65536 out of my define, but I was wrong. rev2023.3.3.43278. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Sign in The calculated expression consists of two operations. Please tell me error: cast from 'void*' to 'int' loses precision, How Intuit democratizes AI development across teams through reusability. Implementing From will result in the Into implementation but not vice-versa. But this code pass the normal variable .. ), For those who are interested. ERROR: incompatible integer to pointer conversion assigning to 'string' (aka 'char *') from 'int', error: cast to 'string' (aka 'char *') from smaller integer type 'int' [-Werror,-Wint-to-pointer-cast], error: incompatible integer to pointer conversion assigning to 'string' (aka 'char *') from 'int' C, warning: initialization of 'unsigned char' from 'uint8_t *' {aka 'unsigned char *'} makes integer from pointer without a cast [-Wint-conversion], Minimising the environmental effects of my dyson brain. The most general answer is - in no way. Can Martian regolith be easily melted with microwaves? Star 675. Getting Command /bin/sh failed with exit code 65 Error with Xcode 5.1 . 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). Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. The difference between the phonemes /p/ and /b/ in Japanese. ../lib/odp-util.c:5603:13: note: expanded from macro 'SCAN_PUT' The bigint data type is intended for use when integer values might exceed the range that is supported by the int data type.. bigint fits between smallmoney and int in the data type precedence chart.. In 64-bit programs, the size of the pointer is 64 bits, and cannot be put into the int type, which remains 32-bit in almost all systems. 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. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. The point is (probably) that the value passed to the thread is an integer value, not really a 'void *'. 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; Therefore it is perfectly valid for the compiler to throw an error for a line like. Remembering to delete the pointer after use so that we don't leak. B Programming Language | What is the History and Concept? The int data type is the primary integer data type in SQL Server. Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. I usually have all automatic conversion warnings effective when developing in C, and I use explicit casting in order to suppress a specific . Type Casting in C Language with Examples - Dot Net Tutorials Whats the grammar of "For those whose stories they are"? How to correctly cast a pointer to int in a 64-bit application? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 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. The text was updated successfully, but these errors were encountered: For integer casts in specific, using into() signals that . *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 . To learn more, see our tips on writing great answers. On most platforms pointers and longs are the same size, but ints and pointers often are not the same size on 64bit platforms. C++ Tutorial => Conversion between pointer and integer lexborisov Modest Public. You need to cast the void* pointer to a char* pointer - and then dereference that char* pointer to give you the char that it points to! How to Cast a void* ponter to a char without a warning? @jackdoe: It's a waste of human life to write code that "you may need in the future". tialized" "-Wno-format" "-Wno-incompatible-pointer-types" "-Werror" "-dM" "-U_MSC_VER" "-D_TIMESPEC_DEFINED" "-D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_SECURE_NO_WA Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. If this is the data to a thread procedure, then you quite commonly want to pass by value. 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 are right! You can also convert values from one type to another explicitly using the cast operator (see Chapter 5 ): ( type_name) expression In the following example, the cast operator causes the division of one integer variable by another to be performed as a floating-point operation: int sum = 22, count = 5; double mean = (double)sum / count; Recovering from a blunder I made while emailing a professor. (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. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? (int) pthread_self() 64int48intuintptr_t (unsigned int) pthread passes the argument as a void*. There is no "correct" way to store a 64-bit pointer in an 32-bit integer. Thanks for contributing an answer to Stack Overflow! But then you need to cast your arguments inside your thread function which is quite unsafe cf. [Solved] Properly casting a `void*` to an integer in C++ Connect and share knowledge within a single location that is structured and easy to search. Offline ImPer Westermark over 11 years ago in reply to Andy Neil Except that you sometimes stores an integer in the pointer itself. I guess the other important fact is that the cast operator has higher precedence that the multiplication operator. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. SCAN_PUT_ATTR(key, ATTR, skey, FUNC); @DietrichEpp can you explain what is race condition with using. Thanks for pointing that out. */void **MatrixIB (unsigned long x, unsigned long y, int size){ void *ptr; void **returnPtr; register unsigned long i, j;
: iPhone Retina 4-inch 64-bit) is selected. Number Type Cast | Qt Forum The text was updated successfully, but these errors were encountered: You signed in with another tab or window. 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. 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. Example: int x=7, y=5; float z; z=x/y; /*Here the value of z is 1*/. You can use a 64 bits integer instead howerver I usually use a function with the right prototype and I cast the function type : Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Dinesh: could you please 1) show us those. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Can anybody explain how to pass an integer to a function which receives (void * ) as a parameter? This page was last modified on 12 February 2023, at 18:25. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Setting a buffer of char* with intermediate casting to int*. Actions. How can this new ban on drag possibly be considered constitutional? To learn more, see our tips on writing great answers. Just want to point out that the purpose of threads is, +1 absolutely true, but if you take you time to write struct {}, you can save a lot of troubles in the future when you want to receive/send more data then just an int. In C (int)b is called an explicit conversion, i.e. If you need to keep the returned address, just keep it as void*. } SCAN_END_SINGLE(ATTR) Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. reinterpret_cast conversion - cppreference.com The following behavior-changing defect reports were applied retroactively to previously published C++ standards. What video game is Charlie playing in Poker Face S01E07? 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). Here is some piece of code where that error occur: /cocos2d-x-2.2.2/cocos2dx/platform/ios/EAGLView.mm:408:18: Cast from pointer to smaller type 'int' loses information.
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