cast to void *' from smaller integer type 'int

If this is the data to a thread procedure, then you quite commonly want to pass by value. You think by casting it here that you are avoiding the problem! Asking for help, clarification, or responding to other answers. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Not the answer you're looking for? 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. Passing arguments to pthread_create - invalid conversion from void(*)() to void(*)(void*). I'm trying to learn pthreads and thing that keeps bugging me is how do i really pass argument to the function. How create a simple program using threads in C? Share Improve this answer Follow answered May 6, 2018 at 7:24 Rahul Anw, the project still build and run normally when i use Xcode 5.0 with iOS 7.0. Casting an open pointer to other pointer types and casting other pointer types to an open pointer does not result in a compile time error. 1. this way you won't get any warning. You can fix this error by replacing this line of code. Losing bytes like thisis called 'truncation', and that's what the first warning is telling you. Note that it's not guaranteed that casting an, Generally this kind of type casting does not lead to any concern as long as the addresses are encoded using the same length as the "variable type" (. How to correctly cast a pointer to int in a 64-bit application? How Intuit democratizes AI development across teams through reusability. a cast of which the programmer should be aware of what (s)he is doing. Can Martian regolith be easily melted with microwaves? What you do here is undefined behavior, and undefined behavior of very practical sort. Where does this (supposedly) Gibson quote come from? *sound/soc/codecs/tlv320aic32x4.c:1202:18: warning: cast to smaller integer type 'enum aic32x4_type' from 'void *' @ 2022-04-22 9:48 kernel test robot 0 siblings, 0 . Press question mark to learn the rest of the keyboard shortcuts. But assuming that it is, as long as the caller and the callee agree, you can do that sort of thing. AC Op-amp integrator with DC Gain Control in LTspice. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. equal to the original pointer: First you are using a define, which is not a variable. Mutually exclusive execution using std::atomic? Why is there a voltage on my HDMI and coaxial cables? Next, when doing pointer arithmetic, the addition operation will use the pointer's type to determine how many bytes to add to it when incrementing it. Sign in Using Kolmogorov complexity to measure difficulty of problems? Can I tell police to wait and call a lawyer when served with a search warrant? How do I force make/GCC to show me the commands? Based on the design of this function, which modification is right. The most general answer is - in no way. There's no proper way to cast this to int in general case. itch" "-I..\include\windows" "-Iinclude" "-I..\include" "-I..\datapath-windows\include" "-IC:\PTHREADS-BUILT\include" "-Xclang" "-fcolor-diagnostics" "-pipe" Wrong. 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. If the sizes are different then endianess comes into play. 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. Example: int x=7, y=5; float z; z=x/y; /*Here the value of z is 1*/. 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. Not the answer you're looking for? You could use this code, and it would do the same thing as casting ptr to (char*). Bulk update symbol size units from mm to map units in rule-based symbology. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Replacing broken pins/legs on a DIP IC package, How to handle a hobby that makes income in US. It's always a good practice to put your #define's in brackets to avoid such surprise. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? Connect and share knowledge within a single location that is structured and easy to search. Have a question about this project? FAILED: lib/libopenvswitch.a.p/odp-util.c.obj Or, they are all wrong. The main point is: a pointer has a platform dependent size. You can use a 64 bits integer instead howerver I usually use a function with the right prototype and I cast the function type : 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, Acidity of alcohols and basicity of amines. Therefore it is perfectly valid for the compiler to throw an error for a line like. GitHub Skip to content Product Solutions Open Source Pricing Sign in Sign up smadaminov / ovs-dpdk-meson-issues Public Notifications Fork 1 Star 1 Code Issues 66 Pull requests Actions Projects 1 Security Insights New issue So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If the function had the correct signature you would not need to cast it explicitly. The problem was there before, you just are being notified of it. 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. For a fairly recent compiler (that supports C99) you should not store or represent address as plain int value. Does Counterspell prevent from any further spells being cast on a given turn? I personally upvoted this answer because by it's first line of text it helped me to understand the reason of this strange error message and what am I, poor idiot, doing :D. Not valid on Windows 64 - long is still 32-bit but pointers are 64-bit. SCAN_PUT_ATTR(key, ATTR, skey, FUNC); property that any valid pointer to void can be converted to this type, If the destination type is bool, this is a boolean conversion (see below). What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? 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. To learn more, see our tips on writing great answers. From what I read about casting in the C11 standard, my feeling is, that it is arguable to emit a warning on an explicit conversion. Then I build my project, I get the error "Cast from pointer to smaller type 'int' loses information" in EAGLView.mm file (line 408) when 64-bit simulators (e.g. ^~~~~~~~~~~~~~~~~~~~~ And, most of these will not even work on gcc4. Your first example is risky because you have to be very careful about the object lifetimes. Why does flowing off the end of a non-void function without returning a value not produce a compiler error? The following behavior-changing defect reports were applied retroactively to previously published C++ standards. In this case, casting the pointer back to an integer is meaningless, because . A cast specifies a conversion from one type to another. Why is there a voltage on my HDMI and coaxial cables? 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. What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. To cast such pointers to 32-bit types and vice versa special functions are used: void * Handle64ToHandle ( const void * POINTER_64 h ) void * POINTER_64 HandleToHandle64 ( const void *h ) long HandleToLong ( const void *h ) unsigned long HandleToUlong ( const void *h ) reinterpret_cast<void *>(42)). ../lib/odp-util.c:5603:13: note: expanded from macro 'SCAN_PUT' The best way is, if one can, do not do such casting, instead, if the same memory address has to be shared for pointer and int (e.g. The text was updated successfully, but these errors were encountered: You signed in with another tab or window. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? 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). And when assigning to a void pointer, all type information is lost. If you cast an int pointer int, you might get back a different integer. vegan) just to try it, does this inconvenience the caterers and staff? 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. */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. 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 ncdu: What's going on with this second size column? byte -> short -> char -> int -> long -> float -> double. ^~~~~~~~~~~~~~~~~~~ What I am trying to emphasis that conversion from int to pointer and back again can be frough with problems as you move from platform to platform. It is commonly called a pointer to T and its type is T*. that any valid pointer to void can be converted to this type, then It is done by the compiler on its own, without any external trigger from the user. Cast characters to unsigned char before converting to larger integer sizes Created by Robert Seacord, last modified by Jill Britton on Oct 03, 2022 Signed character data must be converted to unsigned char before being assigned or converted to a larger signed type. pthread passes the argument as a void*. How to get the error message from the error code returned by GetLastError()? Taking the above declarations of A, D, ch of the . 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. 7.1 New Cast Operations The C++ standard defines new cast operations that provide finer control than previous cast operations. void* -> integer -> void* rather than integer -> void* -> integer. Surely the solution is to change the type of ids from int to type that is sufficiently large to hold a pointer. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. x is a local variable and its lifetime ends as soon as control leaves the scope it was defined in. And in this context, it is very very very common to see programmers lazily type cast the. So,solution #3 works just fine. warning C4311: 'type cast': pointer truncation from 'void *' to 'long' in ECPG test files. 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. I'm unfamiliar with XCode, but the solution should be something like follows: Most of the "solutions" above can lose part of the pointer address when casting to a smaller type. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. How do I set, clear, and toggle a single bit? For example, the main thread could wait for all of the other threads to end before terminating. Remembering to delete the pointer after use so that we don't leak. 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. *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 . 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. But this code pass the normal variable .. SCAN_PUT(ATTR, NULL); Before I update Xcode, my project still can build and run normally with all devices. 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. The problem just occur with Xcode 5.1. Difficulties with estimation of epsilon-delta limit proof. Converting a void* to an int is non-portable way that may work or may not! How to use Slater Type Orbitals as a basis functions in matrix method correctly? 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. rev2023.3.3.43278. If your standard library (even if it is not C99) happens to provide these types - use them. Thanks for contributing an answer to Stack Overflow! To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Please help me compile Chez Scheme. ../lib/odp-util.c:5834:5: error: cast to smaller integer type 'unsigned long' from 'void *' [-Werror,-Wvoid-pointer-to-int-cast] Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. vegan) just to try it, does this inconvenience the caterers and staff? However, I believe that even if the define was for the "65536", it would not be what @kaetzacoatl wanted. ", "? Can Martian regolith be easily melted with microwaves? C / C++ Forums on Bytes. It solved my problem too. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ to the original pointer: The following type designates an unsigned integer type with the Actions. The reinterpret_cast makes the int the size of a pointer and the warning will stop. This is known as implicit type casting or type promotion, compiler automatically converts smaller data type to larger data type. Put your define inside a bracket: without a problem. I guess the other important fact is that the cast operator has higher precedence that the multiplication operator. For example, if you want to store a 'long' value into a simple integer then you can type cast 'long' to 'int'. with ids being an array of ints and touch being a pointer. converted back to pointer to void, and the result will compare equal returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); There is no "correct" way to store a 64-bit pointer in an 32-bit integer. Notifications. Why do small African island nations perform better than African continental nations, considering democracy and human development? RNINGS" "-D_CRT_SECURE_NO_DEPRECATE" -MD -MQ lib/libopenvswitch.a.p/odp-util.c.obj -MF "lib\libopenvswitch.a.p\odp-util.c.obj.d" -o lib/libopenvswitch.a.p/od a is of type int[4], which can be implicitly cast to int* (ie, a pointer to an int) &a is of type int(*)[4] (ie: a pointer to an array of 4 ints). rev2023.3.3.43278. How do I check if a string represents a number (float or int)? Is a PhD visitor considered as a visiting scholar. 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. */ >> -bool >> +enum conversion_safety >> unsafe_conversion_p (tree type, tree expr, bool . What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? The value of float variable is= 37.75. Note:You might receive a runtime exception if the pointer contains a value unsuitable for the context. Does ZnSO4 + H2 at high pressure reverses to Zn + H2SO4? What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? Already on GitHub? 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. Thanks for contributing an answer to Stack Overflow! Asking for help, clarification, or responding to other answers. You may declare a const int variable and cast its reference to the void*. Well occasionally send you account related emails. But, sure, in that specific case you can pass a local variable address, type casting integer to void* [duplicate]. In C (int)b is called an explicit conversion, i.e. Put your define inside a bracket: #define M_TABLE_SIZE (64*1024) Now, you can do: static const void* M_OFFSET = (void*) M_TABLE_SIZE; without a problem. cast to 'double *' from smaller integer type 'unsigned int' The C compiler is gcc, clang version 3.9.1, target aarch64--linux-android, thread model posix. /** Dynamically allocate a 2d (x*y) array of elements of size _size_ bytes. 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). 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.. Therefore, you need to change it to long long instead of long in windows for 64 bits. If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. If you preorder a special airline meal (e.g. 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. By clicking Sign up for GitHub, you agree to our terms of service and Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Setting a buffer of char* with intermediate casting to int*. Making statements based on opinion; back them up with references or personal experience. It modifies >> Wconversion-real.c, Wconversion-real-integer.c and pr35635.c to be more >> specific > > If the patch passes existing tests, I'd be inclined to leave them > tests alone and add new ones that are specific to what this patch > changes. If we want to get the exact value of 7/5 then we need explicit casting from int to float: Example: int x=7, y=5;

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