Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Identify those arcade games from a 1983 Brazilian music video. What I am saying is that it would be safer to use new(5) rather than 5 and deal with it appropriately at the other end. In my case, I was using a 32-bit value that needed to be passed to an OpenGL function as a void * representing an offset into a buffer. ^~~~~~~~~~~~~~~~~~~~ What I am trying to do in that line of code is check to make sure each character in my string is alphabetical. 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. ../lib/odp-util.c:5489:33: note: expanded from macro 'SCAN_PUT_ATTR' @BlueMoon Thanks a lot! You can convert the values from one type to another explicitly using the cast operator as follows (type_name) expression Note the difference between the type casting of a variable and type casting of a pointer. 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". Hence there is no loss in data. The point is (probably) that the value passed to the thread is an integer value, not really a 'void *'. Converting one datatype into another is known as type casting or, type-conversion. As with all cast expressions, the result is: Two objects a and b are pointer-interconvertible if: static_cast may also be used to disambiguate function overloads by performing a function-to-pointer conversion to specific type, as in. ^~~~~~~~~~~~~~~~~~~ The problem just occur with Xcode 5.1. -1, Uggh. On many systems, an 8-bit unsigned int can be stored at any address while an unsigned 32-bit int must be aligned on an address that is a multiple of 4. 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). 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. How can this new ban on drag possibly be considered constitutional? (i.e. A nit: in your version, the cast to void * is unnecessary. lexborisov Modest Public. 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. I'm trying to create a void* from an int. 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. What happens if you typecast as unsigned first? 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. 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. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Infact I know several systems where that does not hold. Casting a pointer to void* and back is valid use of reinterpret_cast<>. Why did Ukraine abstain from the UNHRC vote on China? 1. Recovering from a blunder I made while emailing a professor. The following program casts a double to an int. 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; If you are going to pass the address you typically need to exert some more control over the lifetime of the object. How to use Slater Type Orbitals as a basis functions in matrix method correctly? This will get you a pointer from a 32 bit offset: A function pointer is incompatible to void* (and any other non function pointer). 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. 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 need to pass an actual pointer. Thank you all for your feedback. Why is this sentence from The Great Gatsby grammatical? But you seem to suggest by your answer that the user can pass 5 to pthread_create and then perform the above cast to get it back. Making statements based on opinion; back them up with references or personal experience. When is casting void pointer needed in C? Sign in Converting a pointer to an integer whose result cannot represented in the integer type is undefined behavior is C and prohibited in C++. The proper way is to cast it to another pointer type. pthread passes the argument as a void*. Don't do that. I have a function with prototype void* myFcn(void* arg) which is used as the starting point for a pthread. But the problem has still happened. Implementation-dependent. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Api says this is how i should create thread: So if I want to pass an int what I think I should do is: The second example assumes that a pointer is wide enough to store an int. However, you are also casting the result of this operation to (void*). My code is all over the place now but I appreciate you all helping me on my journey to mastery! 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. 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. It generally takes place when in an expression more than one data type is present. I assumed that gcc makes a 65536 out of my define, but I was wrong. How do I align things in the following tabular environment? Functions return bigint only if the parameter expression is a bigint data type. Floating-point conversions (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. 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. How do I work around the GCC "error: cast from SourceLocation* to int loses precision" error when compiling cmockery.c? Not the answer you're looking for? If that happens soon after the call to pthread_create() then you have a race condition, because there's a chance that the thread will attempt to read x's value after it's life has ended, which invokes undefined behavior. How to make compiler not show int to void pointer cast warnings, incompatible pointer types assigning to 'void (*)(void *)' from 'int (int *)'. 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 [.]) By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. SQL Server does not automatically promote . If this is the data to a thread procedure, then you quite commonly want to pass by value. Remarks. Thus as a result it may be less error prone to generate a pointer dynamcially and use that. All character types are to be converted to an integer. Unless you have a valid address at that value, you are going to invoke undefined behaviour when try to use that pointer. 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; Find centralized, trusted content and collaborate around the technologies you use most. The preprocesor absolutely will not perform arithmetic. for (i=0, j=0; j