Bowsing the source for glibc-2.4 I found this strange stuff in ieee754.h:
What is this :number thing? Can't find much information about it. Some kind of initializer?Code:union ieee754_float { float f; /* This is the IEEE 754 single-precision format. */ struct { #if __BYTE_ORDER == __BIG_ENDIAN unsigned int negative:1; unsigned int exponent:8; unsigned int mantissa:23; #endif /* Big endian. */ #if __BYTE_ORDER == __LITTLE_ENDIAN unsigned int mantissa:23; unsigned int exponent:8; unsigned int negative:1; #endif /* Little endian. */ } ieee; /* This format makes it easier to see if a NaN is a signalling NaN. */ struct { #if __BYTE_ORDER == __BIG_ENDIAN unsigned int negative:1; unsigned int exponent:8; unsigned int quiet_nan:1; unsigned int mantissa:22; #endif /* Big endian. */ #if __BYTE_ORDER == __LITTLE_ENDIAN unsigned int mantissa:22; unsigned int quiet_nan:1; unsigned int exponent:8; unsigned int negative:1; #endif /* Little endian. */ } ieee_nan; };