---
title: "CFStringGetDoubleValue(_:)"
framework: corefoundation
role: symbol
role_heading: Function
path: "corefoundation/cfstringgetdoublevalue(_:)"
---

# CFStringGetDoubleValue(_:)

Returns the primary double value represented by a string.

## Declaration

```swift
func CFStringGetDoubleValue(_ str: CFString!) -> Double
```

## Parameters

- `str`: A string that represents a double value. The only allowed characters are the ASCII digit characters (ASCII 0x30 - 0x39), the plus sign (ASCII 0x2B), the minus sign (ASCII 0x2D), and the period character (ASCII 0x2E).

## Return Value

Return Value The double value represented by str, or 0.0 if there is a scanning error (if the string contains disallowed characters or does not represent a double value).

## Discussion

Discussion Consider the following example: double val = CFStringGetDoubleValue(CFSTR("0.123")); The variable val in this example would contain the value 0.123 after the function is called.

## See Also

### Getting Numeric Values

- [CFStringGetIntValue(_:)](corefoundation/cfstringgetintvalue(_:).md)