Reads one big endian 32bit floating point value from a streamhook.
INPUTS
hook
Streamhook
dataptr
Put the data here
stream
Read from this stream
RESULT
The function returns TRUE on success. On success, the value
read is written into dataptr. On failure, FALSE is returned and the
contents of dataptr are not changed.
NOTES
This function reads big endian values from a streamhook even on
little endian machines.