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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: I am using size_t here, because it is always having the same size as a pointer, no matter the platform. then converted back to pointer to void, and the result will compare Casting type int to const void* - C / C++ 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. Implicit Type Conversion in C with Examples - GeeksforGeeks You need to pass an actual pointer. This is known as implicit type casting or type promotion, compiler automatically converts smaller data type to larger data type. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? This is a fine way to pass integers to new pthreads, if that is what you need. [Solved] Error "Cast from pointer to smaller type 'int' | 9to5Answer There's probably little you can do except look or hope for a fixed 2.x version or upgrade to 3.x (I would assume it's 64-bit safe but this is just a guess, do research this issue before you upgrade). Is it possible to create a concave light? To learn more, see our tips on writing great answers. Thanks for pointing that out. Why is this sentence from The Great Gatsby grammatical? converted back to pointer to void, and the result will compare equal 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. C / C++ Forums on Bytes. What happens if you typecast as unsigned first? Put your define inside a bracket: without a problem. ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ XCode 5.1 is change all architecture to 64 bit. There is absolutely not gurantee that sizeof(int) <= sizeof(void*). *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 . Using an integer address (like &x) is probably wrong, indeed each modification you will execute on x will affect the pass behaviour. Losing bytes like thisis called 'truncation', and that's what the first warning is telling you. itch" "-I..\include\windows" "-Iinclude" "-I..\include" "-I..\datapath-windows\include" "-IC:\PTHREADS-BUILT\include" "-Xclang" "-fcolor-diagnostics" "-pipe" Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Setting a buffer of char* with intermediate casting to int*. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. The only exception is exotic systems with the SILP64 data model, where the size of int is also 64 bits. Terrible solution. 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. Such pointers can be stored in 32-bit data types (for instance, int, DWORD). I need to convert the argument to an int for later use: The compiler (GCC version 4.2.4) returns the error: You can cast it to an intptr_t type. Cast a smaller integer to a larger integer - community - The Rust windows meson: cast to 'HANDLE' (aka 'void *') from smaller integer Thanks for contributing an answer to Stack Overflow! How do I set, clear, and toggle a single bit? 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. Casting Pointers - IBM It solved my problem too. If the original pointer value represents an address of a byte in memory that does not satisfy the alignment requirement of the target type, then the resulting pointer value is unspecified. @Martin York: No, it doesn't depend on endiannness. You should perform type conversion based on 64bit build system because the type "int" supports only -32768 ~ 32768. Is pthread_join a must when using pthread in linux? The mapping in pointer<->integer casts is implementation defined, but the intent was that if the pointer type is large enough and isn't forcefully aligned (, But that's different. Making statements based on opinion; back them up with references or personal experience. This explicit cast clearly tells the compiler "Shut up, I know that this code does not look correct, but I do know what I am doing". Narrowing Casting (manually) - converting a larger type to a . If you need to keep the returned address, just keep it as void*. Does a summoned creature play immediately after being summoned by a ready action? Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, "what happen when typcating normal variable to void* or any pointer variable?" You are correct, but cocos actually only uses that address as a unique id. As Ferruccio said, int must be replaced with intptr_t to make the program meaningful. 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. reinterpret_cast conversion - cppreference.com And in this context, it is very very very common to see programmers lazily type cast the. Did i have to face to unexpected runtime issues, i guess not, i've found another discussion on this -. If you write ((char*)ptr + 1), it will advance the pointer 1 byte, because a "char" is 1 byte. c - type casting integer to void* - Stack Overflow Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Why is this sentence from The Great Gatsby grammatical? eg. Why is there a voltage on my HDMI and coaxial cables? error: cast from 'void*' to 'int' loses precision - Stack Overflow Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. You can use a 64 bits integer instead howerver I usually use a function with the right prototype and I cast the function type : 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. The cast back to int * is not, though. } SCAN_END_SINGLE(ATTR) 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. You are just making it bigger by tricking the compiler and the ABI. 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. There's no proper way to cast this to int in general case. If you are planning to use pthreads and you are planning to pass the pass function to pthread_create, you have to malloc/free the arguments you are planning to use (even if the threaded function just need a single int). If the function had the correct signature you would not need to cast it explicitly. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. A long long would not work for 32bit systems and a long would not work for 64 bit Windows (while 64bit Unix and Unix-like systems like OS X use the LP64 data model, in which a long is 64bit, 64bit Windows uses the LLP64 data model, in which a long has a size of 32bit (http://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models)). Windows has 32 bit long only on 64 bit as well. But this code pass the normal variable .. "-I.." "-Iinclude\openflow" "-I..\include\openflow" "-Iinclude\openvswitch" "-I..\include\openvsw If the original type is a void *, converting to an int may lose date on platforms where sizeof(void *) != sizeof(int) (which is true of LP64 programming model). Casting arguments inside the function is a lot safer. ), Styling contours by colour and by line thickness in QGIS. A sane compiler may throw a warning on lines like this but by no way it should throw an error, because this code is NOT wrong, it is just potentially error-prone, but can be perfectly valid. How to Cast a void* ponter to a char without a warning? How to use Slater Type Orbitals as a basis functions in matrix method correctly? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. what does it mean to convert int to void* or vice versa? Connect and share knowledge within a single location that is structured and easy to search. Using Kolmogorov complexity to measure difficulty of problems? */ >> -bool >> +enum conversion_safety >> unsafe_conversion_p (tree type, tree expr, bool . And when assigning to a void pointer, all type information is lost. Converting one datatype into another is known as type casting or, type-conversion. SCAN_SINGLE("skb_priority(", uint32_t, u32, OVS_KEY_ATTR_PRIORITY); 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 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 C++ Tutorial => Conversion between pointer and integer (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 c pthreads 4 10.3k 2 21 2015-06-05 Type conversions - cplusplus.com a cast of which the programmer should be aware of what (s)he is doing. Implicit conversions - cppreference.com The high-order 9 bits of the number are used to hold a flag value, and the result is converted back into a pointer. @jackdoe: It's a waste of human life to write code that "you may need in the future". If you cast an int pointer int, you might get back a different integer. 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. Connect and share knowledge within a single location that is structured and easy to search. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? That's not a good idea if the original object (that was cast to void*) was an integer. How to correctly cast a pointer to int in a 64-bit application? To learn more, see our tips on writing great answers. When is casting void pointer needed in C? The compiler issues the "cast from integer to pointer of different size" warning whenever the value of an integer is converted to a pointer, especially when the memory allocated to a pointer is smaller than the memory allocated to an integer data type. "-D_FILE_OFFSET_BITS=64" "-Wall" "-Winvalid-pch" "-g" "-Wthread-safety" "-Wno-microsoft-enum-forward-reference" "-Wno-unused-function" "-Wno-sometimes-unini void* -> integer -> void* rather than integer -> void* -> integer. linux c-pthreads: problem with local variables. 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. @Shahbaz you could but I will not suggest to a C newbie to use globals. So,solution #3 works just fine. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? 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. Functions return bigint only if the parameter expression is a bigint data type. Thanks Jonathan, I was thinking about my answer in another thread: AraK is correct, passing integers a pointers are not necessarily interchangeable. This will get you a pointer from a 32 bit offset: A function pointer is incompatible to void* (and any other non function pointer).
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