Use StrToFloat to convert a string, S, to a floating-point value. S must consist of an optional sign (+ or -), a string of digits with an optional decimal point, and an optional mantissa. The mantissa consists of 'E' or 'e' followed by an optional sign (+ or -) and a whole number. Leading and trailing blanks are ignored.
The DecimalSeparator global variable or its TFormatSettings equivalent defines the character that is used as a decimal point. Thousand separators and currency symbols are not allowed in the string. If S doesn't contain a valid value, StrToFloat raises an EConvertError exception.
The first form of StrToFloat is not thread-safe, because it uses localization information contained in global variables. The second form of StrToFloat, which is thread-safe, refers to localization information contained in the FormatSettings parameter. Before calling the thread-safe form of StrToFloat, you must populate FormatSettings with localization information. To populate FormatSettings with a set of default locale values, call GetLocaleFormatSettings.