Message <Context> a pointer to <type1> is being cast to a pointer to <type2>. Using ANSI aliasing rules, the compiler may subsequently assume that the two pointer types are pointing to different storage locations. Description The C standard allows a compiler to assume that these two pointer types will point to different storage locations. The compiler will make this assumption whenever ansi aliasing is enabled on the command line, either directly or via another switch. The cast in itself does not violate aliasing rules, e.g. you might cast the pointer value back to an allowed type before you use it to access memory. But the compiler cannot generally determine whether or not you do that. If your code accesses the memory designated by this pointer value using both of these pointer types, you may get unexpected results when ansi aliasing is enabled. User Action Casting through pointer to void will silence this message. But if the end result is that the same memory still gets accessed through different types that are not permitted under the aliasing rules, you may still get unexpected results. If compiling without ansi aliasing corrects the behavior of your program, your code almost certainly violates the aliasing rules in a way that the compiler cannot detect.