string_to_floating_point() accepts exactly one argument, which must be of string_type. This may be a variable or a constant. However, in practise, it is normally a variable (since, otherwise, a constant of floating_point_type could simply be used directly, instead of invoking string_to_floating_point() to process a string constant). In any case, if the argument is a variable, it will not be altered by string_to_floating_point().
string_to_floating_point() produces a return value of floating_point_type.
string_to_floating_point() examines the string given as an
argument, and interprets it (if possible) as a
decimal (base 10) number, possibly in scientific notation (e.g.
"2.3e5" would denote etc.). Providing that
the string can be interpreted successfully in this way,
string_to_floating_point() will produce the internal binary
representation (i.e. of floating_point_type) of this number as
the return value. If the string cannot be interpreted in
this way (e.g. "rhubarb" or "forty-two" or "(01)
704-5000" etc.) then a runtime exception will be generated and
the program will terminate abnormally.