Instance Method

write(to:atomically:encoding:)

Writes the contents of the receiver to the URL specified by url using the specified encoding.

Declaration

func write(to url: URL, atomically useAuxiliaryFile: Bool, encoding enc: UInt) throws

Parameters

url

The URL to which to write the receiver. Only file URLs are supported.

useAuxiliaryFile

If true, the receiver is written to an auxiliary file, and then the auxiliary file is renamed to url. If false, the receiver is written directly to url. The true option guarantees that url, if it exists at all, won’t be corrupted even if the system should crash during writing.

The useAuxiliaryFile parameter is ignored if url is not of a type that can be accessed atomically.

enc

The encoding to use for the output.

error

If there is an error, upon return contains an NSError object that describes the problem. If you are not interested in details of errors, you may pass in NULL.

Return Value

true if the URL is written successfully, otherwise false (if there was a problem writing to the URL or with the encoding).

Discussion

This method stores the specified encoding with the file in an extended attribute under the name com.apple.TextEncoding. The value contains the IANA name for the encoding and the CFStringEncoding value for the encoding, separated by a semicolon. The CFStringEncoding value is written as an ASCII string containing an unsigned 32-bit decimal integer and is not terminated by a null character. One or both of these values may be missing. Examples of the value written include the following:

  • MACINTOSH;0

  • UTF-8;134217984

  • UTF-8;

  • ;3071

The methods init(contentsOfFile:usedEncoding:), init(contentsOf:usedEncoding:), stringWithContentsOfFile:usedEncoding:error:, and stringWithContentsOfURL:usedEncoding:error: use this information to open the file using the right encoding.