Clang similarly warns that “magnitude of floating-point constant too large for type double”. The number 2^5000 represented in C as 0x1.0p5000 is totally in the range of double which goes up to inf. T.c:5:3: warning: floating constant exceeds range of ‘double’ There is no reason to worry of undefined behavior caused by overflow in either floating-point arithmetic or in the conversion of a double to a float. This means that for C compilation platforms that implement IEEE 754 for floating-point the condition “the value can be represented in the new type” is always true. IEEE 754 floating-point defines +inf and -inf values so that any real number can be approximated in the target IEEE 754 format (albeit when it ends up represented as an infinity not precisely). Still in practice modern compilation platforms if they provide floating-point features at all provide either exactly IEEE 754 binar圓2 and binary64 formats and computations or the same formats and a close approximation of the same computations.

The C standard does not mandate IEEE 754 floating-point arithmetic. Compiler makers cannot change their mind willy-nilly as if it was undefined behavior:ġ When a value with integer type is converted to another integer type other than _Bool if the value can be represented by the new type it is unchanged.Ģ Otherwise if the new type is unsigned the value is converted by repeatedly adding or subtracting one more than the maximum value that can be represented in the new type until the value is in the range of the new type.ģ Otherwise the new type is signed and the value cannot be represented in it either the result is implementation-defined or an implementation-defined signal is raised. And you can trust that they will continue to do so because it's implementation-defined.

The C99 standard allows for an implementation-defined signal to be raised but in practice the widespread compilation platforms provide two's complement behavior. In contrast the behavior of overflows in conversions from integer type to signed integer type is implementation-defined. A previous post on this blog was a reminder that in C signed integer arithmetic overflow is undefined behavior.

Convert mac address to float point