Getting the IEEE Single-precision bits for a float

Question

I need to write an IEEE single-precision floating point number to a 32-bit hardware register at a particular address. To do that, I need to convert a variable of type float

Answer 1

EDIT: The union solution works everywhere I have tried it but somewhere on SO I had been pointed at standards that showed it didnt have to work. See the link below in the comments to find a LOT more info on this (Thank you Daniel!). Supposed to work or not supposed to work I would use it with care, I imagine endianness, etc gets involved as well (doubles broken into bytes, etc).

Another solution is a dummy asm function. For example on arm:

.globl echo 
echo:
   bx lr


unsigned int echo ( float );
...
unsigned int ra; float f;
f=1.0;
ra=echo(f);

some disassembly is required, needs to be on a system that doesnt have an fpu and/or uses gprs for carrying around floats.

memcpy as already mentioned is the cleanest and most reliable and portable solution (be aware of endianness).