If all bits are 0 (example I memset the floating point variable to all 0), what is the value of IEEE floating point used in gcc? It is guaranteed to be 0.0 ?
I guess for other floating point formats result may vary. But my question is specific to IEEE floating point used with gcc.
If the implementation is IEEE 754 compliant there exist special cases for different bit-combinations, like documented here.
For your case: When all bits (sign, exponent, mantissa) are zero the floating point value represents also zero, as defined by IEEE 754. More specifically, that value is a "positive zero", also written as +0.