On 12/12/2011 01:48 PM, BELBACHIR Selim wrote: > Everything seems good when I use a union instead of "*((int *)(&af))". > > But I think that "*((int *)(&af))" is a valid syntax to get the > integer representation of my floating point value (in my test case > 0x3F800000 for 1.0f in IEEE-754). It may be target dependant but I > think it should work on target having 32 bits float and integer (and > IEEE754 compliance).
It's legal syntax, but it's not semantically legal. http://www.open-std.org/jtc1/sc22/wg...docs/n1124.pdf chapter 6.5 An object shall have its stored value accessed only by an lvalue expression that has one of the following types: — a type compatible with the effective type of the object, — a qualified version of a type compatible with the effective type of the object, — a type that is the signed or unsigned type corresponding to the effective type of the object, — a type that is the signed or unsigned type corresponding to a qualified version of the effective type of the object, — an aggregate or union type that includes one of the aforementioned types among its members (including, recursively, a member of a subaggregate or contained union), or — a character type. See also labs.qt.nokia.com/2011/06/10/type-punning-and-strict-aliasing/ Andrew.
